Improvement of electrical characteristics in SPC-Si TFT employing H_2 plasma treatment

摘要

We fabricated PMOS SPC-Si TFTs which exhibit better uniformity than ELA poly-Si TFTs, and superior electrical stability compare to a-Si:H TFTs. We applied various H_2 plasma treatments on the solid phase crystallized silicon (SPC-Si) active layer prior to SiO_2 gate insulator deposition, in order to improve the interface of SPC-Si. When the H_2 plasma treatment with 100W power of PE-CVD was applied in the SPC-Si for 5 minutes, the electrical characteristics of the fabricated SPC-Si TFT was improved. It showed V_(TH) of -3.91V, field effect mobility of 22.68cm~2/Vs and subthreshold swing of 0.64. We applied hot carrier stress (V_(GS)= 14.91V,V_(DS)=- 15V, for 2,000 sec.) in the SPC-Si TFT. The electrical characteristics were not altered. We also applied constant bias stress (V_(GS)=-15V, V_(DS)=-10V for 20,000 sec.) in SPC-Si TFT. The V_(TH) of SPC-Si TFT was not increased under the constant bias stress. The stability of SPC-Si TFT was better than that of poly-Si TFT and a-Si:H TFT.