搭桥晶粒多晶硅薄膜晶体管直流电应力下的退化行为与退化机制研究

摘要

Degradation behaviors and degradation mechanisms of bridged-grain (BG)polycrystalline silicon thin film transistors (TFTs)under DC bias stresses are studied and investigated.Compared to normal poly-Si TFTs,BG poly-Si TFTs exhibits better negative bias temperature instability (NBTI), better self-heating (SH)reliability and better hot carrier (HC)reliability.All these DC reliability im-provements come from BG lines inside the active channel.By selectively doping the active channel in BG poly-Si TFTs,boron-hydrogen bonds formation at oxide/channel interface and grain boundaries, Joule heat diffusion enhancement at channel length direction and lateral electric field reduction at the drain side are respectively responsible for the improved NBTI reliability,SH reliability and HC relia-bility.All test results indicate that such high performance and high reliable BG poly-Si TFTs have great potential in system-on-panel applications.%研究了搭桥晶粒(BG)多晶硅薄膜晶体管(TFT)在直流电应力下的退化行为和退化机制。与普通多晶硅 TFT 相比,BG 多晶硅 TFT 展现出更好的直流应力可靠性。主要体现在 BG 多晶硅 TFT 拥有更好的直流负偏压温度不稳定性(NBTI)可靠性,更好的直流自加热(SH)可靠性,更好的直流热载流子(HC)可靠性。有源沟道区的 BG 结构是上述直流应力可靠性提高的主要原因。更好的 NBTI 的可靠性主要源于沟道内的硼氢键的形成；更好的 SH 可靠性主要源于在沟道长度方向上更快的焦耳热扩散率；更好的 HC 可靠性主要源于漏端横向电场(E x )的减弱。所有的测试结果都表明,这种高性能高可靠性的 BG 多晶硅 TFT 在片上系统中具有很大的应用前景。