Peking University IGZO TFT Ling Wang 2013 1

Peking University 外界气氛对IGZO TFT 可靠性的影响 Ling Wang 2013 -1 -17

原理 Peking University VBS<0, 衬偏效应，ΔVth>0 VBS>0, 衬偏效应，ΔVth<0 H 2 O进入active layer，到达界面，SS变化 Jae Kyeong Jeong,

气氛对电场应力的影响 Device A：unpassivated Device B: passivated Stress voltage：|Vg|=20 V，Vd=0 V Peking University • PBS：

气氛对电场应力的影响 Peking University Top gate TFT：a, c: Al 2 O 3, b, d: Al

气氛对光应力的影响 Peking University • B: PBS/NBS 都不变 A：NBS 负漂移， light generated holes charge trap解释不通

Model Peking University • Stretched exponential model-charge trap Et-channel/dielectric average barrier • 缺点：unpassivated device

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Peking University 外界气氛对IGZO TFT 可靠性的影响 Ling Wang 2013 -1 -17

原理 Peking University VBS<0, 衬偏效应，ΔVth>0 VBS>0, 衬偏效应，ΔVth<0 H 2 O进入active layer，到达界面，SS变化 Jae Kyeong Jeong, et al, APL, 93, 2008 3

气氛对电场应力的影响 Device A：unpassivated Device B: passivated Stress voltage：|Vg|=20 V，Vd=0 V Peking University • PBS： ΔVth. A>ΔVth. B-charge trap ‖ ΔVth. A-ΔVth. B –back interface 吸收O 2生成O 2 • NBS: ΔVth. B ≈0；ΔVth. A <0 -back interface吸收H 2 O，形成H 2 O+ 4 Yang et al. , Appl. Phys. Lett. 96, 213511 � 2010�

气氛对电场应力的影响 Peking University Top gate TFT：a, c: Al 2 O 3, b, d: Al 2 O 3+Si. Nx , Vg=60 V • 大电场下， Vth shift，charge trap a：ln(ΔVth) ∝ln t: (the trapped electron redistributed in the insulator) b：ΔVth ∝ln t unpassivated IGZO TFT 电应力可靠性：小电场：back interface 与气氛的作用大电场：charge trap Lee et al. , Appl. Phys. Lett. 94, 222112 (2009) 5

气氛对光应力的影响 Peking University • B: PBS/NBS 都不变 A：NBS 负漂移， light generated holes charge trap解释不通 Device A：unpassivated Device B: passivated Stress voltage：|Vg|=20 V，Vd=0 V 气氛的影响：光提供能量促进O 2 -从背界面脱离，并吸附H 2 O形成H 2 O+ Shinhyuk Yang，Appl. Phys. Lett. 96, 213511 , 2010 6

Model Peking University • Stretched exponential model-charge trap Et-channel/dielectric average barrier • 缺点：unpassivated device 主导机理是back interface与气氛的反应，不是charge trap • 下周作：继续探讨气氛的影响，寻找定量模型 J. M. Lee, Appl. Phys. Lett. , vol. 93, no. 9, p. 093504, Sep. 2008 8