Analysis of Off�]state Leakage Currents in Poly-Si FinTFTs with Wide Drain by Microwave Annealing

Abstract

In this study, polycrystalline silicon fin-like thin-film transistors (poly-Si FinTFTs) with a wide drain structure are fabricated. The off leakage current of poly-Si FinTFTs with various extended wide drain lengths (L EX) is investigated. As L EX increases, the longitudinal electric field at the intrinsic drift/N+ drain junction decreases and improves the off leakage current derived from longitudinal band-to-band tunneling (L-BTBT). The off leakage current of poly-Si FinTFTs at different temperatures is also analyzed to investigate the leakage mechanisms. For poly-Si FinTFTs with a small L EX (= 0 and 0.8 mm), the weak dependence of leakage current on temperature indicates that the band-to-band tunneling (BTBT) is dominant. For poly-Si FinTFTs with a large L EX of 1.6 mm, the strong dependence of leakage current on temperature and the weak dependence of leakage current on drain voltage indicate that trapassisted tunneling (TAT) is the dominant leakage mechanism. These results indicate that it is gate-induced drain leakage (GIDL), resulting from L-BTBT, that is effectively suppressed by increasing L EX .