塑料基底a-Si∶H TFT制备技术

Fabrication Techniques of a-Si∶H TFT on Plastic Substrate

采用PECVD工艺,在300℃下在50μm厚的Kapton E高分子塑料片上制备了底栅结构a-Si∶H TFT阵列（20×20）。用傅里叶变换红外光谱仪表征了a-Si∶H薄膜的结构,用二探针法和四探针法分别表征了a-Si∶H薄膜和n＋a-Si∶H薄膜的电导率。a-Si∶H薄膜中的H（原子数分数）约为15.6%,H主要以Si H和Si H2基团的形式存在,其电导率为8.2×10^-78.8×10^-6S/cm;n＋a-Si∶H薄膜的电导率为3.8×10^-3S/cm。所制备的TFT具有以下性能：Ioff≈1×10^-14A,Ion≈1×10-9A,Ion/Ioff≈105,Vth≈5V,μ≈0.113cm2/（V.s）,S≈2.5V/dec,满足TFT-LCD等平板显示器件的开关寻址电路要求。

Bottom gate structure a-Si∶H TFT array was deposited by standard PECVD process at 300 ℃ on Kapton E plastic substrate with thickness of 50 μm.The structure of a-Si∶H film was characterized by IR spectrum.The electrical conductivity of a-Si∶H film and n＋ a-Si∶H film is measured by two probes and four probes method,respectively.The H atom is of 15.6% content in a-Si∶H film and mainly appeared in SiH and SiH2 group.The electrical conductivity of a-Si∶H film is 8.2×10-78.8×10-6 S/cm,and that of n＋ a-Si∶H film is 3.8×10-3 S/cm.The TFTs have a threshold voltage of 5 V,sub threshold slope of 2.5 V/dec,linear mobility of 0.113 cm2/（V·s）and on/off current ratio of 105.The results show that the a-Si∶H TFTs on plastic substrate fabricated in this process can be used in TFT-LCD and some other switch addressable circuits of flat panel display.