高移動度酸化物半導体材料 - KOBELCO

1 /Vol. 65 No. 2 Sep. 2015 67 Flat Panel Display FPD FPD TV Thin Film Transistor TFT TFT a-Si Low-Temperature Polycrystalline-Silicon LTPS LTPS In-Ga-Zn-O IGZO 1 1 a-Si LTPS IGZO IGZO FE a-Si 20 a-Si TFT

2 IGZO 1 IGZO 2007 Society for Information Display SID LG 2 2008 SAMSUNG 3 2012 2013 LG Display 55 organic light emitting diode OLED TV IGZO TFT 2 4 11 In-Sn-Zn-O ITZO ZnO IWO 30cm2/Vs LTPS p MOS High Mobility OXIDE Semiconducting Material FEATURE : Electronic and Electric technologies (Advanced Materials and Apparatuses) We have developed a new Zn-free oxide semiconducting material (KOS-H07) with high field effect mobility above 80cm2/Vs in a thin film transistor (TFT).

3 The field effect mobility is 8 times higher than that of conventional In-Ga-Zn-O (IGZO)-TFT. The TFT of etch stop layer structure requires nothing beyond the conventional process for a TFT. The new oxide TFT shows excellent characteristics with a positive threshold voltage of , sub-threshold swing (SS) of We also investigated the activation energy of the TFT compared to IGZO-TFT, so it can be assumed to have the same behavior of electron conduction as TFT. 1 Dr. Toshihiro KUGIMIYA 1 Mototaka OCHI 1 Hiroshi GOTO 1 Shinya MORITA 1 Yasuyuki TAKANASHI 1 2 ( ) 1 IGZO History of display using IGZO material 1 Table1 Comparison of semiconducting materials used in FPD 2 Dr.

4 Rer. nat. Moriyoshi KANAMARU68,0#& 45&&- &/(*/&&3*/( 3&10354 Vol. 65 No. 2 Sep. 2015 TFT Id Vg 60cm2/Vs TFT 0V TFT 1. IGZO Zn 1 2 a IGZO In Ga Zn=1 1 1 Al PAN Cu H2O2 IGZO Zn 2 b PAN IGZO TFT Id Vg 2 a Zn Zn 2 b TFT Id Vg hump 44 Zn KOS-H07 3 IGZO In-Ga-Zn-Sn-O IGZTO KOS-B02 KOS-H07 PAN H2O2 Ti 2.))

5 TFT 2. 1 KOS-H07 TFT KOS-H07 TFT 3 a KOS-H07 TFT 3 b Etch Stop Layer ESL ESL TFT 40nm 3 b TFT IGZO TFT 4 Ar O2 O2 KOS-H07 IGZO 20 30 3 b TFT KOS-H07 TFT Id Vg 5 SS IGZO TFT 10

6 LTPS p MOS 2 Table2 Compositions of semiconducting materials used in FPD 3 Table3 Comparison of solubility to etchants for oxide thin films 2 a IGZO Zn b Id Vg (a) Zn composition at IGZO film surface after etchant immersion, (b) Id Vg characteristics /Vol. 65 No. 2 Sep. 2015 69 0V 1018cm 3 12 6 Id Vg OLED TFT 2. 2 KOS-H07 TFT KOS-H07 5 Id Vg 0V TFT Id Vg 7 3 a ESL TFT b TFT (a) Schematic of cross-sectional ESL-typed TFT, (b)

7 Fabrication process flow 4 Dependence of sputtering rate on oxygen partial pressure 5 KOS-H07 TFT Id Vg Id Vg characteristics of TFT using KOS-H07 film 6 KOS-H07 TFT Id Vg Id Vg characteristics of TFT using KOS-H07 film 7 a Id Vg b (a) Dependence of Id Vg characteristics on measurement temperature, (b) Determination of activation energy70,0#& 45&&- &/(*/&&3*/( 3&10354 Vol. 65 No. 2 Sep. 2015 13 Id = Ido exp Ea/KBT .. 1 KB T 7 b Ea 8 IGZO TFT Ea 2.))

8 3 KOS-H07 TFT KOS-H07 TFT 4 Negative Bias Temperature Stress NBTS Negative Bias Temperature Illumination Stress NBTIS 9 a b NBTS NBTIS TFT NBTIS 14 TFT KOS-H07 KOS-H07 X 10 11 X 11 a 3. KOS-H07 95 10 KOS-H07 TFT TEM KOS-H07 Cross-sectional TEM photographs of TFT using KOS-H07 film, and electron diffraction of KOS-H07 film 11 KOS-H07 X a b 350 C XRD results of KOS-H07 films, (a) as-deposited, (b) after annealing at 350 C 8 KOS-H07 IGZO Comparison of activation energies of KOS-H07 and IGZO flims 9 TFT a NBTS b Stress test results of (a) NBTS, (b) NBTIS in TFTs 4 TFT Table4 Stress test conditions of TFTs /Vol.

9 65 No. 2 Sep. 2015 7110 2 cm 50cm 12 5 KOS-H07 LTPS LTPS KOS-H07 Si 15 1 K. Nomura et al. Nature, 2004, , H. Lee et al. SID Symposium Digest of Technical Papers, 2007, J. Lee et al. SID Symposium Digest of Technical Papers, 2008, M. Ryu et a. Appl. Phys. Lett. 2009, , E. Fukumoto et al.

10 , Journal of the Society for Information Display. 2011, , J. Song et al. SID Symposium Digest of Technical Papers, 2013, H. Chiang et al. Appl. Phys. Lett. 2005, , P. Gorm et al. Appl. Phys. Lett. 2007, , B. Ynaglioglu et al. Appl. Phys. Lett. 2006, , Y. Ye et al. SID Symposium Digest of Technical Papers. 2013, T. Kizu et al. Appl. Phys. Lett. 2014, , .. 2013, 82 , M. Chowdhury et al. Appl. Phys. Lett. 2013, , S. Nakano et al. SID Symposium Digest of Technical Papers. 2012, J. Sanghum et al. IEDM Tech. Dig. 2010, 12 5 KOS-H07 KOS-H07 sputtering target for 5th generation li