Petitioner Bluehouse Global Ltd.
`Petitioner Bluehouse Global Ltd.
`
`Ex. 1001
`EX. 1001
`
`

`

`USOO8492840B2
`
`(12) Umted States Patent
`(10) Patent No.:
`US 8,492,840 B2
`
`Yamazaki et a].
`(45) Date of Patent:
`Jul. 23, 2013
`
`(54) SEMICONDUCTOR DEVICE HAVING AN
`OXIDE SEMICONDUCTOR LAYER
`
`(75)
`
`Inventors: Shunpei Yamazaki, Setagaya (JP);
`Hiromichi G0d0, Isehara (JP); Hideomi
`Suzawa, Atsugi (JP); Shinya Sasagawa,
`Chigasaki (JP); Motomu Kurata,
`Isehara (JP); Mayumi Mikami, Atsugi
`(JP)
`
`5,744,864 A
`6,294,274 B1
`6,563,174 B2
`3:33:33 3:
`7,061,014 B2
`7,064,346 B2
`7,105,868 B2
`7’211’825 B2
`
`4/1998 Cillessen et a1.
`9/2001 Kawazoe et a1.
`5/2003 Kawasaki et a1.
`ggggg ¥:k‘:::a1;tl:lt.al'
`6/2006 Hosono et a1.
`6/2006 Kawasaki et a1.
`9/2006 Nause et a1.
`5/2007 Shlh et 31
`(Continued)
`
`(73) Assignee: Semiconductor Energy Laboratory
`Co., Ltd., Atsugi-shi, Kanagawa-ken
`(JP)
`
`EP
`EP
`
`FOREIGN PATENT DOCUMENTS
`1737044 A
`12/2006
`2226847 A
`9/2010
`(Continued)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 153 days.
`
`OTHER PUBLICATIONS
`International Search Report (Application No. PCT/JP2010/073886)
`Dated Feb. 15, 2011.
`
`(21) Appl. No.: 13/008,285
`
`(22)
`
`Filed:
`
`Jan. 18, 2011
`
`(65)
`
`(30)
`
`Prior Publication Data
`
`US 2011/0180796 A1
`
`Jul. 28, 2011
`
`Foreign Application Priority Data
`
`(JP) ................................. 2010-012540
`
`Jan. 22, 2010
`(51)
`Int. Cl.
`H01L 27/12
`(52) US. Cl.
`USPC ..................................... 257/347; 257/E29.14
`(58) Field of Classification Search
`USPC ............................................. 257/347, E2914
`See application file for complete search history.
`
`(2006.01)
`
`(56)
`
`References Cited
`
`US. PATENT DOCUMENTS
`
`5648662 A.
`5,731,856 A
`
`7n997 Zhangetm.
`3/1998 Kim et al.
`
`(Continued)
`
`Primary Examiner 7 Howard Weiss
`Assistant Examiner 7 Steven Rao
`
`(74) Attorney, Agent, or Firm 7 Eric J. Robinson; Robinson
`Intellectual Property Law Oflice, PC.
`
`ABSTRACT
`(57)
`An object is to provide a semiconductor device including an
`oxide semiconductor, which maintains favorable characteris-
`tics and achieves miniaturization. The semiconductor device
`includes an oxide semiconductor layer, a source electrode and
`a drain eleCtrode in coma“ With the OXide semiconducmr
`layer, a gate electrode overlapping with the oxide semicon-
`ducmrlayers andagate 11151112“ng layer PIOVided between the
`oxide semiconductor layer and the gate electrode, in which
`the source electrode and the drain electrode each include a
`
`first conductive layer, and a second conductive layer having a
`region which extends in a channel length direction from an
`end portion of the first conductive layer.
`
`23 Claims, 13 Drawing Sheets
`
`144 146
`
`148
`
`160
`
`100
`
`143b
`145b
`142b
`
`144 146
`
`148
`
`145a
`
`1428
`
`

`

`US 8,492,840 B2
`
`Page 2
`
`7,282,782
`7,297,977
`7,323,356
`7,385,224
`7,402,506
`7,411,209
`7,453,065
`7,453,087
`7,462,862
`7,468,304
`7,501,293
`7,576,394
`7,598,520
`7,674,650
`7,732,819
`2001/0046027
`2002/0056838
`2002/0132454
`2003/0146452
`2003/0189401
`2003/0218222
`2004/0038446
`2004/0127038
`2005/0017302
`2005/0199959
`2006/0035452
`2006/0043377
`2006/0091793
`2006/0108529
`2006/0108636
`2006/0110867
`2006/0113536
`2006/0113539
`2006/0113549
`2006/0113565
`2006/0169973
`2006/0170111
`2006/0197092
`2006/0208977
`2006/0228974
`2006/0231882
`2006/0238135
`2006/0244107
`2006/0284171
`2006/0284172
`2006/0292777
`2007/0024187
`2007/0046191
`2007/0052025
`2007/0054507
`2007/0090365
`2007/0108446
`2007/0152217
`2007/0172591
`2007/0187678
`2007/0187760
`2007/0194379
`2007/0252928
`2007/0272922
`2007/0278490
`2007/0287296
`2008/0006877
`2008/0038882
`2008/0038929
`2008/0048183
`2008/0050595
`2008/0073653
`2008/0083950
`2008/0106191
`2008/0128689
`2008/0129195
`2008/0166834
`2008/0182358
`2008/0224133
`2008/0254569
`2008/0258139
`2008/0258140
`2008/0258141
`
`U.S. PATENT DOCUMENTS
`B2
`10/2007
`Hoffman et al.
`B2
`11/2007
`Hoffman et al.
`B2
`1/2008
`Hosono et al.
`B2
`6/2008
`Ishii et al.
`B2
`7/2008
`Levy et al.
`B2
`8/2008
`Endo et al.
`B2
`11/2008
`Saito et al.
`B2
`11/2008
`Iwasaki
`B2
`12/2008
`Hoffman et al.
`B2
`12/2008
`Kaji et al.
`B2
`3/2009
`Ito et a1.
`B2
`8/2009
`Furuta et a1.
`B2
`10/2009
`Hirao et al.
`B2
`3/2010
`Akimoto et al.
`B2
`6/2010
`Akimoto et al.
`A1
`11/2001
`Tai et al.
`A1
`5/2002
`Ogawa
`A1
`9/2002
`Ohtsu et al.
`A1
`8/2003
`Chiang
`A1
`10/2003
`Kido et al.
`A1
`11/2003
`Wager et a1.
`A1
`2/2004
`Takeda et a1.
`A1
`7/2004
`Carcia et a1.
`A1
`1/2005
`Hoffman
`A1
`9/2005
`Chiang et al.
`A1
`2/2006
`Carcia et a1.
`A1
`3/2006
`Hoffman et al.
`A1
`5/2006
`Baude et a1.
`A1
`5/2006
`Saito et al.
`A1
`5/2006
`Sano et al.
`A1
`5/2006
`Yabuta et al.
`A1
`6/2006
`Kumomi et a1.
`A1
`6/2006
`Sano et al.
`A1
`6/2006
`Den et al.
`A1
`6/2006
`Abe et al.
`A1
`8/2006
`Isa et a1.
`A1
`8/2006
`Isa et a1.
`A1
`9/2006
`Hoffman et al.
`A1
`9/2006
`Kimura
`A1
`10/2006
`Thelss et a1.
`A1
`10/2006
`Kim et al.
`A1
`10/2006
`Kimura
`A1
`11/2006
`Sugihara et al.
`A1
`12/2006
`Levy et al.
`A1
`12/2006
`Ishii
`A1
`12/2006
`Dunbar
`A1
`2/2007
`Shin et al.
`A1
`3/2007
`Saito
`A1
`3/2007
`Yabuta
`A1
`3/2007
`Kaji et al.
`A1
`4/2007
`Hayashi et al.
`A1
`5/2007
`Akimoto
`A1
`7/2007
`Lai et al.
`A1
`7/2007
`Seo et a1.
`A1
`8/2007
`Hirao et al.
`A1
`8/2007
`Furuta et a1.
`A1
`8/2007
`Hosono et al.
`A1
`11/2007
`Ito et a1.
`A1
`11/2007
`Kim et al.
`A1
`12/2007
`Hirao et al.
`A1
`12/2007
`Chang
`A1
`1/2008
`Mardilovich et a1.
`A1
`2/2008
`Takechi et al.
`A1
`2/2008
`Chang
`A1
`2/2008
`Ohsawa et al.
`A1
`2/2008
`Nakagawara et al.
`A1
`3/2008
`Iwasaki
`A1
`4/2008
`Pan et al.
`A1
`Kawase
`5/2008
`A1
`6/2008
`Lee et a1.
`A1
`6/2008
`Ishizaki et al.
`A1
`7/2008
`Kim et al.
`A1
`7/2008
`Cowdery-Corvan et al.
`A1
`9/2008
`Park et al.
`A1
`10/2008
`Hoffman et al.
`A1
`10/2008
`Ito et a1.
`A1
`10/2008
`Lee et a1.
`A1
`10/2008
`Park et al.
`
`.................. 257/347
`
`2008/0258143 A1
`2008/0296568 A1
`2009/0068773 A1
`2009/0073325 A1
`2009/0114910 A1
`2009/0134383 A1
`2009/0134399 A1
`2009/0152506 A1
`2009/0152541 A1
`2009/0186437 A1
`2009/0186445 A1
`2009/0189155 A1
`2009/0189156 A1
`2009/0269881 A1
`2009/0278122 A1
`2009/0280600 A1
`2009/0286351 A1
`2010/0003783 A1
`2010/0038639 A1
`2010/0065844 A1
`2010/0092800 A1
`2010/0109002 A1
`2010/0297809 A1
`2011/0193080 A1
`2011/0210326 A1
`
`10/2008 Kim et a1.
`12/2008 Ryu et al.
`3/2009 Lai et al.
`3/2009 Kuwabara et al.
`5/2009 Chang
`5/2009 Imahayashi et al.
`5/2009 Sakakura et al.
`6/2009 Umeda et a1.
`6/2009 Maekawa et al.
`7/2009 Akimoto
`7/2009 Akimoto
`7/2009 Akimoto
`7/2009 Akimoto
`10/2009 Furuta et al.
`11/2009 Hosono et al.
`11/2009 Hosono et al.
`11/2009 Hirao et al.
`1/2010 Akimoto
`2/2010 Akimoto
`3/2010 Tokunaga
`4/2010 Itagaki et al.
`5/2010 Itagaki et al.
`11/2010 Imahayashi et al.
`8/2011 Yamazaki et al.
`9/2011 Suzawa et al.
`
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`WO
`WO
`WO
`WO
`
`FOREIGN PATENT DOCUMENTS
`60-198861
`10/1985
`63-210022 A
`8/1988
`63-210023 A
`8/1988
`63-210024 A
`8/1988
`63-215519 A
`9/1988
`63-239117 A
`10/1988
`63-265818 A
`11/1988
`05-251705 A
`9/1993
`08-264794
`10/1996
`11-505377
`5/1999
`2000-044236 A
`2/2000
`2000-150900
`5/2000
`2002-076356 A
`3/2002
`2002-289859 A
`10/2002
`2003-086000 A
`3/2003
`2003-086808 A
`3/2003
`2004-103957
`4/2004
`2004-273614 A
`9/2004
`2004-273732 A
`9/2004
`WO-2004/114391
`12/2004
`WO-2007/058329
`5/2007
`WO-2007/089048
`8/2007
`WO-2007/142167
`12/2007
`
`OTHER PUBLICATIONS
`
`Written Opinion (Application No. PCT/JP2010/073886) Dated Feb.
`15, 201 1.
`Fortunato.E et a1., “Wide-Bandgap High-Mobility ZNO Thin-Film
`Transistors Produced at Room Temperature,”, Appl. Phys. Lett.
`(Applied Physics Letters), Sep. 27, 2004, vol. 85, No. 13, pp. 2541-
`2543.
`Dembo.H et a1., “RFCPUS on Glass and Plastic Substrates Fabri-
`cated by TFT Transfer Technology,”, IEDM 05: Technical Digest of
`International Electron Devices Meeting, Dec. 5, 2005, pp. 1067-
`1069.
`
`Ikeda.T et a1., “Full-Functional System Liquid Crystal Display Using
`CG-Silicon Technology,”, SID Digest ’04 : SID International Sym-
`posium Digest of Technical Papers, 2004, vol. 35, pp. 860-863.
`Park.J et a1., “Improvements in the Device Characteristics of Amor-
`phous Indium Gallium Zinc Oxide Thin-Film Transistors by Ar
`Plasma Treatment,”, Appl. Phys. Lett. (Applied Physics Letters), Jun.
`26, 2007, vol. 90, No. 26, pp. 262106-1-262106-3.
`Takahashi.M et a1., “Theoretical Analysis of IGZO Transparent
`Amorphous Oxide Semiconductor,”, IDW ’08 : Proceedings of the
`15th International Display Workshops, Dec. 3, 2008, pp. 1637-1640.
`Hayashi.R et a1., “42.1: Invited Paper: Improved Amorphous In-Ga-
`Zn-O TFTS,”, SID Digest ’08 : SID International Symposium Digest
`ofTechnical Papers, May 20, 2008, vol. 39, pp. 621-624.
`
`

`

`US 8,492,840 B2
`Page 3
`
`Masuda.S et al., “Transparent thin film transistors using ZnO as an
`active channel layer and their electrical properties,”, J. Appl. Phys.
`(Journal oprplied Physics), Feb. 1, 2003, vol. 93, No. 3, pp. 1624-
`1630.
`Asakuma.N et al., “Crystallization and Reduction of Sol-Gel-De-
`rived Zinc Oxide Films by Irradiation With Ultraviolet Lamp,”, Jour-
`nal of Sol-Gel Science and Technology, 2003, vol. 26, pp. 181-184.
`Osada.T et al., “15.2: Development of Driver-Integrated Panel using
`Amorphous In-Ga—Zn-Oxide TFT,”, SID Digest ’09 : SID Interna-
`tional Symposium Digest of Technical Papers, May 31, 2009, pp.
`184-187.
`Nomura.K et al., “Carrier transport in transparent oxide semiconduc-
`tor with intrinsic structural randomness probed using single-crystal-
`line InGaO3(ZnO)5 films,”, Appl. Phys. Lett. (Applied Physics Let-
`ters), Sep. 13, 2004, vol. 85, No. 11, pp. 1993-1995.
`Li.C et al., “Modulated Structures of Homologous Compounds
`InMO3(ZnO)m (M:In,Ga; m:Integer) Described by Four-Dimen-
`sional Superspace Group,”, Journal of Solid State Chemistry, 1998,
`vol. 139, pp. 347-355.
`Son.K et al., “42.4L: Late-News Paper: 4 Inch QVGA AMOLED
`Driven by the Threshold Voltage Controlled Amorphous GIZO
`(Ga203-In203-ZnO) TFT,”, SID Digest ’08 : SID International
`Symposium Digest of Technical Papers, May 20, 2008, vol. 39, pp.
`633-636.
`Lee.J et al., “World’s Largest (15-Inch) XGA AMLCD Panel Using
`IGZO Oxide TFT,”, SID Digest ’08 : SID International Symposium
`Digest of Technical Papers, May 20, 2008, vol. 39, pp. 625-628.
`Nowatari.H et al., “60.2: Intermediate Connector With Suppressed
`Voltage Loss for White Tandem OLEDS,”, SID Digest ’09 : SID
`International Symposium Digest of Technical Papers, May 31, 2009,
`vol. 40, pp. 899-902.
`Kanno.H et al., “White Stacked Electrophosphorecent Organic
`Light-Emitting Devices Employing MOO3 as a Charge-Generation
`Layer,”, Adv.Mater. (Advanced Materials), 2006, vol. 18, No. 3, pp.
`339-342.
`Tsuda.K et al., “Ultra Low Power Consumption Technologies for
`Mobile TFT-LCDs,”, IDW ’02 : Proceedings of the 9th International
`Display Workshops, Dec. 4, 2002, pp. 295-298.
`Van de Walle.C, “Hydrogen as a Cause of Doping in Zinc Oxide,”,
`Phys. Rev. Lett. (Physical Review Letters), Jul. 31, 2000, vol. 85, No.
`5, pp. 1012-1015.
`Fung.T et al., “2-D Numerical Simulation of High Performance
`Amorphous In-Ga-Zn-O TFTs for Flat Panel Displays,”, AM-FPD
`’08 Digest ofTechnical Papers, Jul. 2, 2008, pp. 251-252, The Japan
`Society of Applied Physics.
`Jeong.J et al., “3.1: Distinguished Paper: 12.1-Inch WXGA
`AMOLED Display Driven by Indium-Gallium-Zinc Oxide TFTs
`Array,”, SID Digest ’08 : SID International Symposium Digest of
`Technical Papers, May 20, 2008, vol. 39, No. 1, pp. 1-4.
`Park.J et al., “High performance amorphous oxide thin film transis-
`tors with self-aligned top-gate structure,”, IEDM 09: Technical
`Digest of International Electron Devices Meeting, Dec. 7, 2009, pp.
`191-194.
`Kurokawa.Y et al., “UHF RFCPUS on Flexible and Glass Substrates
`for Secure RFID Systems,”, Journal of Solid-State Circuits, 2008,
`vol. 43, No. 1, pp. 292-299.
`Ohara.H et al., “Amorphous In-Ga-Zn-Oxide TFTs with Suppressed
`Variation for 4.0 inch QVGA AMOLED Display,”, AM-FPD ’09
`Digest of Technical Papers, Jul. 1, 2009, pp. 227-230, The Japan
`Society of Applied Physics.
`Coates.D et al., “Optical Studies of the Amorphous Liquid-
`Cholesteric Liquid Crystal Transition:The “Blue Phase”,”, Physics
`Letters, Sep. 10, 1973, vol. 45A, No. 2, pp. 115-116.
`Cho.D et al., “21.2:AL and SN-Doped Zinc Indium Oxide Thin Film
`Transistors for AMOLED Back-Plane,”, SID Digest ’09 : SID Inter-
`national Symposium Digest of Technical Papers, May 31, 2009, pp.
`280-283.
`Lee.M et al., “15.4:Excellent Performance of Indium-Oxide-Based
`Thin-Film Transistors by DC Sputtering,”, SID Digest ’09 : SID
`International Symposium Digest of Technical Papers, May 31, 2009,
`pp. 191-193.
`Jin.D et al., “65.2:Distinguished Paper:World-Largest (6.5") Flexible
`Full Color Top Emission AMOLED Display on Plastic Film and Its
`
`Bending Properties,”, SID Digest ’09 : SID International Symposium
`Digest of Technical Papers, May 31, 2009, pp. 983-985.
`Sakata.J et al., “Development of 4.0-In. AMOLED Display With
`Driver Circuit Using Amorphous
`In-Ga-Zn-Oxide TFTs,”,
`IDW ’09 :Proceedings of the 16th International Display Workshops,
`2009, pp. 689-692.
`Park.J et al., “Amorphous Indium-Gallium-Zinc Oxide TFTs and
`Their Application for Large Size AMOLED,”, AM-FPD ’08 Digest of
`Technical Papers, Jul. 2, 2008, pp. 275-278.
`Park.S et al., “Challenge to Future Displays: Transparent AM-OLED
`Driven by Peald Grown ZnO TFT,”, IMID ’07 Digest, 2007, pp.
`1249-1252.
`Godo.H et al., “Temperature Dependence of Characteristics and
`Electronic Structure for Amorphous In-Ga-Zn-Oxide TFT,”, AM-
`FPD ’09 Digest ofTechnical Papers, Jul. 1, 2009, pp. 41-44.
`Osada.T et al., “Development of Driver-Integrated Panel Using
`Amorphous In-Ga—Zn-Oxide TFT,”, AM-FPD ’09 Digest of Techni-
`cal Papers, Jul. 1, 2009, pp. 33-36.
`Hirao.T et al., “Novel Top-Gate Zinc Oxide Thin-Film Transistors
`(ZnO TFTs) for AMLCDS,”, Journal ofthe SID, 2007, vol. 15, No. 1,
`pp. 17-22.
`Hosono.H, “68.3:Invited Paper:Transparent Amorphous Oxide
`Semiconductors for High Performance TFT,”, SID Digest ’07 : SID
`International Symposium Digest of Technical Papers, 2007, vol. 38,
`pp. 1830-1833.
`Godo.H et al., “P-9:Numerical Analysis on Temperature Dependence
`of Characteristics ofAmorphous In-Ga—Zn-Oxide TFT,”, SID Digest
`’09 : SID International Symposium Digest of Technical Papers, May
`31, 2009, pp. 1110-1112.
`Ohara.H et al., “21 3:40 In. QVGA AMOLED Display Using In-Ga-
`Zn-Oxide TFTs With a Novel Passivation Layer,”, SID Digest ’09 :
`SID International Symposium Digest of Technical Papers, May 31,
`2009, pp. 284-287.
`Miyasaka.M, “Suftla Flexible Microelectronics on Their Way to
`Business,”, SID Digest ’07 : SID International Symposium Digest of
`Technical Papers, 2007, vol. 38, pp. 1673-1676.
`Chern.H et al., “An Analytical Model for the Above-Threshold Char-
`acteristics of Polysilicon Thin-Film Transistors,”, IEEE Transactions
`on Electron Devices, Jul. 1, 1995, vol. 42, No. 7, pp. 1240-1246.
`Kikuchi.H et al., “39.1:Invited Paper:Optically Isotropic Nano-
`Structured Liquid Crystal Composites for Display Applications,”,
`SID Digest ’09 : SID International Symposium Digest of Technical
`Papers, May 31, 2009, pp. 578-581.
`Asaoka.Y et al., “29.1: Polarizer-Free Reflective LCD Combined
`With Ultra Low-Power Driving Technology,”, SID Digest ’09 : SID
`International Symposium Digest of Technical Papers, May 31, 2009,
`pp. 395-398.
`Lee.H et al., “Current Status of, Challenges to, and Perspective View
`of AM-OLED,”, IDW ’06 : Proceedings of the 13th International
`Display Workshops, Dec. 7, 2006, pp. 663-666.
`Kikuchi.H et al., “62.2:Invited Paper:Fast Electro-Optical Switching
`in Polymer-Stabilized Liquid Crystalline Blue Phases for Display
`Application,”, SID Digest ’07 : SID International Symposium Digest
`ofTechnical Papers, 2007, vol. 38, pp. 1737-1740.
`Nakamura.M, “Synthesis of Homologous Compound with New
`Long-Period Structure,”, NIRIM Newsletter, Mar. 1, 1995, vol. 150,
`pp. 1-4.
`Kikuchi.H et al., “Polymer-Stabilized Liquid Crystal Blue Phases,”,
`Nature Materials, Sep. 1, 2002, vol. 1, pp. 64-68.
`Kimizuka.N et al., “Spinel,YBFE204, and YB2FE307 Types of
`Structures for Compounds in the IN203 and SC203 -A203-BO Sys-
`tems [Ag Fe, Ga, Or Al; B: Mg, Mn, Fe, Ni, Cu,Or Zn] at Tempera-
`tures Over 1000" C.,”, Journal of Solid State Chemistry, 1985, vol.
`60, pp. 382-384.
`Kitzerow.H et al., “Observation of Blue Phases in Chiral Networks,”,
`Liquid Crystals, 1993, vol. 14, No. 3, pp. 911-916.
`Costello.M et al., “Electron Microscopy of a Cholesteric Liquid
`Crystal and Its Blue Phase,”, Phys. Rev. A (Physical Review. A), May
`1, 1984, vol. 29, No. 5, pp. 2957-2959.
`Meiboom.S et al., “Theory of the Blue Phase of Cholesteric Liquid
`Crystals,”, Phys. Rev. Lett. (Physical Review Letters), May 4, 1981,
`vol. 46, No. 18, pp. 1216-1219.
`
`

`

`US 8,492,840 B2
`
`Page 4
`
`Park.Sang-Hee et al., “42.3: Transparent ZnO Thin Film Transistor
`for the Application of High Aperture Ratio Bottom Emission AM-
`OLED Display,”, SID Digest ’08 : SID International Symposium
`Digest of Technical Papers, May 20, 2008, vol. 39, pp. 629-632.
`Orita.M et al., “Mechanism ofElectrical Conductivity of Transparent
`InGaZnO4,”, Phys. Rev. B (Physical Review. B), Jan. 15, 2000, vol.
`61, No. 3, pp. 1811-1816.
`Nomura.K et al., “Amorphous Oxide Semiconductors for High-Per-
`formance Flexible Thin-Film Transistors,”, Jpn. J. Appl. Phys. (Japa-
`nese Journal of Applied Physics), 2006, vol. 45, No. 5B, pp. 4303-
`4308.
`Janotti.A et al., “Native Point Defects in ZnO,”, Phys. Rev. B (Physi-
`cal Review. B), Oct. 4, 2007, vol. 76, No. 16, pp. 165202-1-165202-
`22.
`Park.J et al., “Electronic Transport Properties ofAmorphous Indium-
`Gallium-Zinc Oxide Semiconductor Upon Exposure to Water,”,
`Appl. Phys. Lett. (Applied Physics Letters), 2008, vol. 92, pp.
`072104-1-072104-3.
`Hsieh.H et al., “P-29:Modeling ofAmorphous Oxide Semiconductor
`Thin Film Transistors and Subgap Density of States,”, SID
`Digest ’08 : SID International Symposium Digest of Technical
`Papers, 2008, vol. 39, pp. 1277-1280.
`Janotti.A et al., “Oxygen Vacancies in ZnO,”, Appl. Phys. Lett.
`(Applied Physics Letters), 2005, vol. 87, pp. 122102-1-122102-3.
`Oba.F et al., “Defect energetics in ZnO: A hybrid Hartree-Fock
`density functional study,”, Phys. Rev. B (Physical Review. B), 2008,
`vol. 77, pp. 245202-1-245202-6.
`oxide
`conductive
`transparent
`Orita.M et
`al.,
`“Amorphous
`InGaO3(ZnO)m (m<4):aZn4s conductor,”, Philosophical Magazine,
`2001, vol. 81, No. 5, pp. 501-515.
`Ho sono .H et al., “Working hypothesis to explore novel wide band gap
`electrically conducting amorphous oxides and examples,”, J. Non-
`Cryst. Solids (Journal of Non-Crystalline Solids), 1996, vol. 198-
`200, pp. 165-169.
`Mo.Y et al., “Amorphous Oxide TFT Backplanes for Large Size
`AMOLED Displays,”, IDW ’08 : Proceedings ofthe 6th International
`Display Workshops, Dec. 3, 2008, pp. 581-584.
`Kim.S et al., “High-Performance oxide thin film transistors pas-
`sivated by various gas plasmas,”, 214th ECS Meeting, 2008, No.
`2317.
`
`Clark.S et al., “First Principles Methods Using CASTEP,”, Zeitschrift
`fur Kristallographie, 2005, vol. 220, pp. 567-570.
`and
`Lany.S
`et
`al.,
`“Dopability,
`Intrinsic
`Conductivity,
`Nonstoichiometry of Transparent Conducting Oxides,”, Phys. Rev.
`Lett. (Physical Review Letters), Jan. 26, 2007, vol. 98, pp. 045501-
`1-045 501-4.
`Park.J et al., “Dry etching of ZnO films and plasma-induced damage
`to optical properties,”, J. Vac. Sci. Technol. B (Journal of Vacuum
`Science & Technology B), Mar. 1, 2003, vol. 21, No. 2, pp. 800-803.
`Oh.M et al., “Improving the Gate Stability of ZnO Thin-Film Tran-
`sistors With Aluminum Oxide Dielectric Layers,”, J. Electrochem.
`Soc. (Journal ofthe Electrochemical Society), 2008, vol. 155, No. 12,
`pp. H1009-H1014.
`Ueno.K et al., “Field-Effect Transistor on SrTiO3 With Sputtered
`Al203 Gate Insulator,”, Appl. Phys. Lett. (Applied Physics Letters),
`Sep. 1, 2003, vol. 83, No. 9, pp. 1755-1757.
`Nomura et al., “Room-Temperature Fabrication ofTransparent Flex-
`ible Thin-Film Transistors Using Amorphous Oxide Semiconduc-
`tors,” Nature, Nov. 25, 2004, vol. 432, pp. 488-492.
`Prins et al., “A Ferroelectric Transparent Thin-Film Transistor,” Appl.
`Phys. Lett. (Applied Physics Letters), Jun. 17, 1996, vol. 68, No. 25,
`pp. 3650-3652.
`Nakamura et al., “The Phase Relations in the InZO3-GaZZnO4-ZnO
`System at 1350" C.,” Journal of Solid State Chemistry, Aug. 1, 1991,
`vol. 93, No. 2, pp. 298-315.
`Kimizuka et al., “Syntheses and Single-Crystal Data of Homologous
`Compounds, InZO3(ZnO)m (m : 3, 4, and 5), InGaO3(ZnO)3, and
`GaZO3(ZnO)m (m : 7, 8, 9, and 16) in the InZO3-ZnGaZO4-ZnO
`System,” Journal ofSolid State Chemistry, Apr. 1, 1995, vol. 116, No.
`1,pp.170-178.
`Nakamura et al., “Syntheses and crystal structures of new homolo-
`gous compounds, indium iron zinc oxides (InFeO3(ZnO)m) (m: natu-
`ral number) and related compounds,” Kotai Butsuri (Solid State
`Physics), 1993, vol. 28, No. 5, pp. 317-327.
`Nomura et al., “Thin-Film Transistor Fabricated in Single-Crystal-
`line Transparent Oxide Semiconductor,” Science, May 23, 2003, vol.
`300, No. 5623, pp. 1269-1272.
`
`* cited by examiner
`
`

`

`US. Patent
`
`Jul. 23, 2013
`
`Sheet 1 of 13
`
`US 8,492,840 B2
`
`FIG'1A 144146 148
`
`160
`
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`
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`
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`
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`
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`
`142b
`
`FIG. 10
`
`144 146
`
`148
`
`180
`
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`
`142a
`
`145a
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`
`
`I
`
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`
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`
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`190
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`
`
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`
`
`
`
`A
`
`
`a
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`100
`
`

`

`US. Patent
`
`Jul. 23, 2013
`
`Sheet 2 of 13
`
`US 8,492,840 B2
`
`143b
`
`145b
`
`FIG. 2F
`
`““““
`
`
`
`
`

`

`US. Patent
`
`Jul. 23, 2013
`
`Sheet 3 of 13
`
`US 8,492,840 B2
`
`FIG. 3A
`
`142a
`
`FIG. 3B
`
`143a
`
`
`
`143b
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`
`
`FIG. 3E
`
`
`
`FIG. 3F
`
`148
`
`180
`
`
`
`

`

`US. Patent
`
`Jul. 23, 2013
`
`Sheet 4 of 13
`
`US 8,492,840 B2
`
`F1(3.‘4
`
`243b
`
`_ 200
`
`242b
`
`245b
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`

`

`US. Patent
`
`Jul. 23, 2013
`
`Sheet 5 of 13
`
`US 8,492,840 B2
`
`§§§§S§§§§§§§§S§§§§S§§§§§§§§S
`
`V
`245b
`
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`
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`
`FIG. SE
`
`2453
`
`FIG. SF
`
`244 246 248
`
`280
`
`
`
`

`

`US. Patent
`
`Jul. 23, 2013
`
`Sheet 6 of 13
`
`US 8,492,840 B2
`
`FIG. 6A1
`
`FIG. GB
`
`2
`
`5th Lme /3/0 4th Lme
`4th Line
`,....I....
`310
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`
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`
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`
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`
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`
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`
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`
`

`

`U.S. Patent
`
`Jul. 23, 2013
`
`Sheet 7 of 13
`
`US 8,492,840 B2
`
`FIG. 7A
`
`81(1)
`
`320 300 BL“)
`
` B7nF
`
`

`

`US. Patent
`
`Jul. 23, 2013
`
`Sheet 8 of 13
`
`US 8,492,840 B2
`
`FIG. 8A
`
`Vdd
`
`l
`
`Vbias
`
`Vref
`
`terminal A
`
`FIG. SB
`
`FIG. 80
`
`Vdd
`
`V2 |—°Sn
`
`GND
`
`

`

`US. Patent
`
`Jul. 23, 2013
`
`Sheet 9 of 13
`
`US 8,492,840 B2
`
`FIG. 9A
`
`
`
`FIG. 90
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`

`

`US. Patent
`
`Jul. 23, 2013
`
`Sheet 10 of 13
`
`US 8,492,840 B2
`
`FIG. 10A
`
`746
`
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`

`

`US. Patent
`
`Jul. 23, 2013
`
`Sheet 11 of 13
`
`US 8,492,840 B2
`
`Fifi, HA
`
` Q
`
`333
`
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`
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`
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`
`ififi
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`
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`

`

`US. Patent
`
`Jul. 23, 2013
`
`Sheet 12 of 13
`
`US 8,492,840 B2
`
`FEE, 12A
`
`
`
`{3
`
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`
`i, [am]
`
`

`

`US. Patent
`
`Jul. 23, 2013
`
`Sheet 13 of 13
`
`US 8,492,840 B2
`
`FIG. 13
`
` 0
`
`300
`
`400
`
`100
`
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`
`L [nm]
`
`

`

`US 8,492,840 B2
`
`1
`SEMICONDUCTOR DEVICE HAVING AN
`OXIDE SEMICONDUCTOR LAYER
`
`TECHNICAL FIELD
`
`A technical field of the present invention relates to a semi-
`conductor device. Note that semiconductor devices herein
`
`refer to general elements and devices which function by uti-
`lizing semiconductor characteristics.
`
`BACKGROUND ART
`
`There are a wide variety of metal oxides and such metal
`oxides are used for various applications. Indium oxide is a
`well-known material and has been used for transparent elec-
`trodes required in liquid crystal display devices or the like.
`Some metal oxides have semiconductor characteristics.
`
`The examples of such metal oxides having semiconductor
`characteristics are, for example, tungsten oxide, tin oxide,
`indium oxide, zinc oxide, and the like. A thin film transistor in
`which a channel formation region is formed using such metal
`oxides is already known (for example, see Patent Documents
`1 to 4, Non-Patent Document 1, and the like).
`As metal oxides, not only single-component oxides but
`also multi-component oxides are known. For example,
`InGaO3(ZnO)m (m: natural number) having a homologous
`phase is known as a multi-component oxide semiconductor
`including In, Ga, and Zn (for example, see Non-Patent Docu-
`ments 2 to 4 and the like).
`Furthermore, it is confirmed that an oxide semiconductor
`including such an In%a7Zn-based oxide is applicable to a
`channel
`formation region of a thin film transistor (for
`example, see Patent Document 5, Non-Patent Documents 5
`and 6, and the like).
`
`REFERENCES
`
`Patent Documents
`
`[Patent Document 1] Japanese Published Patent Application
`No. S60-198861
`
`[Patent Document 2] Japanese Published Patent Application
`No. H8-264794
`
`[Patent Document 3] Japanese Translation of PCT Interna-
`tional Application No. H11-505377
`[Patent Document 4] Japanese Published Patent Application
`No. 2000-150900
`
`[Patent Document 5] Japanese Published Patent Application
`No. 2004-103957
`
`Non-Patent Document
`
`[Non-Patent Document 1] M. W. Prins, K. O. Grosse-Holz, G
`Muller, J. F. M. Cillessen, J. B. Giesbers, R. P. Weening,
`and R. M. Wolf, “A ferroelectric transparent thin-film tran-
`sistor”, Appl. Phys. L621, 17 Jun. 1996, Vol. 68 pp. 3650-
`3652
`
`[Non-Patent Document 2] M. Nakamura, N. Kimizuka, and T.
`Mohri, “The Phase Relations in the In2037Ga2ZnO4i
`ZnO System at 13500 C.”, J. Solid State Chem, 1991, Vol.
`93, pp. 298-315
`[Non-Patent Document 3] N. Kimizuka, M. Isobe, and M.
`Nakamura,
`“Syntheses
`and Single-Crystal Data of
`Homologous Compounds, In203(ZnO)m (m:3, 4, and 5),
`InGaO3(ZnO)3, and Ga203(ZnO)m (m:7, 8, 9, and 16) in
`the In2037ZnGa2047ZnO System”,
`J. Solid State
`Chem, 1995,Vol. 116, pp. 170-178
`
`2
`[Non-Patent Document 4] M. Nakamura, N. Kimizuka, T.
`Mohri, and M. Isobe, “Syntheses and crystal structures of
`new homologous compounds, indium iron zinc oxides (In-
`FeO3(ZnO)m)
`(mznatural number) and related com-
`pounds”, KOTAI BUTSURI (SOLID STATE PHYSICS),
`1993, Vol. 28, No. 5, pp. 317-327
`[Non-Patent Document 5] K. Nomura, H. Ohta, K. Ueda, T.
`Kamiya, M. Hirano, and H. Hosono, “Thin-film transistor
`fabricated in single-crystalline transparent oxide semicon-
`ductor”, SCIENCE, 2003, Vol. 300, pp. 1269-1272
`[Non-Patent Document 6] K. Nomura, H. Ohta, A. Takagi, T.
`Kamiya, M. Hirano, and H. Hosono, “Room-temperature
`fabrication of transparent flexible thin-film transistors
`using amorphous oxide semiconductors”, NA TURE, 2004,
`Vol. 432 pp. 488-492
`
`DISCLOSURE OF INVENTION
`
`In order to achieve high-speed operation, low power con-
`sumption, cost reduction, or the like of a transistor,
`it is
`necessary to miniaturize a transistor.
`In the case where a transistor is miniaturized, defects gen-
`erated in a manufacturing process become a major problem.
`For example, each of a source electrode and a drain electrode
`and a channel formation region are electrically connected;
`however, disconnections, poor connections, and the like may
`occur due to a decrease in coverage by the miniaturization.
`In addition, in the case where a transistor is miniaturized, a
`problem of a short-channel effect is also caused. The short-
`channel effect refers to degradation of electrical characteris-
`tics which becomes obvious with miniaturization of a tran-
`
`sistor (a reduction in channel length (L)). The short-channel
`effect results from the effect of an electric field of a drain
`
`electrode on a source electrode. Specific examples of the
`short-channel effect are a decrease in threshold voltage, an
`increase in subthreshold swing (S value), an increase in leak-
`age current, and the like. In particular, it is known that a
`transistor including an oxide semiconductor has smaller off
`current at a room temperature as compared to a transistor
`including silicon. This is attributed to the fact that carriers
`generated by thermal excitation are small, that is, carrier
`density is small. In the transistor in which a material whose
`carrier density is small is used as described above, a short-
`channel effect such as a decrease in a threshold voltage tends
`to be caused easily.
`Thus, according to an embodiment of the disclosed inven-
`tion, it is an object of the present invention to provide a
`semiconductor device which achieves miniaturization while
`
`the defects are suppressed. Further, it is another object of the
`present invention to provide a semiconductor device which
`achieves miniaturization while favorable characteristics are
`maintained.
`One embodiment of the disclosed invention is a semicon-
`
`ductor device which includes an oxide semiconductor layer, a
`source electrode and a drain electrode in contact with the
`
`oxide semiconductor layer, a gate electrode overlapping with
`the oxide semiconductor layer, and a gate insulating layer
`provided between the oxide semiconductor layer and the gate
`electrode, in which the source electrode and the drain elec-
`trode each include a first conductive layer, and a second
`conductive layer having a region which extends in a channel
`length direction from an end portion of the first conductive
`layer.
`In the above semiconductor device, each of the first con-
`ductive layer and the second conductive layer preferably has
`a tapered shape.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`

`

`US 8,492,840 B2
`
`3
`In the above semiconductor device, sidewall insulating
`layers are preferably provided over the regions of each of the
`second conductive layer.
`Another embodiment of the disclosed invention is a semi-
`conductor device which includes an oxide semiconductor
`
`layer, a source electrode and a drain electrode in contact with
`the oxide semiconductor layer, a gate electrode overlapping
`with the oxide semiconductor layer, and a gate insulating
`layer provided between the oxide semiconductor layer and
`the gate electrode, in which the source electrode and the drain
`electrode each include a first conductive layer and a second
`conductive layer having a higher resistance than the first
`conductive layer, where the second conductive layer is in
`contact with the oxide semiconductor layer.
`Another embodiment of the disclosed invention is a semi-
`conductor device which includes an oxide semiconductor
`
`layer, a source electrode and a drain electrode in contact with
`the oxide semiconductor layer, a gate electrode overlapping
`with the oxide semiconductor layer, and a gate insulating
`layer provided between the oxide semiconductor layer and
`the gate electrode, in which the source electrode and the drain
`electrode each include a first conductive layer and a second
`conductive layer having a higher resistance than the first
`conductive layer, where the second conductive layer and the
`first conductive layer are in contact with the oxide semicon-
`ductor layer.
`In the above semiconductor device, the second conductive
`layer is preferably a nitride of a metal.
`In the above semiconductor device, the thickness of the
`second conductive layer is preferably from 5 nm to 15 nm.
`Another embodiment of the disclosed invention is a semi-
`conductor device which includes an oxide semiconductor
`
`10
`
`15
`
`20
`
`25
`
`30
`
`layer including a channel formation region, a source electrode
`and a drain electrode in contact with the channel formation
`
`35
`
`region, a gate electrode overlapping with the channel forma-
`tion region, and a gate insulating layer provided between the
`oxide semiconductor layer and the gate electrode, in which a
`region in each of the source electrode and the drain electrode
`in contact with the channel formation region of the oxide
`semiconductor layer has a higher resistance than other
`regions.
`In the above semiconductor device, each of the source
`electrode and the drain electrode is in contact with the oxide
`
`semiconductor layer at an end portion thereof, and an insu-
`lating layer is provided between the source electrode and the
`oxide semiconductor layer or between the drain electrode and
`the oxide semiconductor layer.
`Note that semiconductor devices herein refer to general
`devices which function by utilizing semiconductor character-
`istics. For example, a display device, a memory device, an
`integrated circuit, and the like are included in the category of
`the semiconductor device.
`
`In this specification and the like, the terms “over” and
`“below” do not necessarily mean “directly on” and “directly
`below”, respectively, in the description of a physical relation-
`ship between components. For example, the expression “a
`gate electrode over a gate insulating layer” can mean the case
`where there is an additional component between the gate
`insulating layer and the gate electrode. Moreover, the terms
`such as “over” and “below” are only used for convenience of
`description and can include the case where the relation of
`components is reversed, unless otherwise specified.
`In addition, in this specification and the like, the term such
`as “electrode” or “wiring” does not limit a function of a
`component. For example, an “electrode” is sometimes used as
`