High hole and electron mobilities in nanocrystalline silicon thin-film transistors

Abstract We report for the first time high hole and electron mobilities in directly deposited plasma-enhanced chemical vapor deposition (PECVD) hydrogenated nanocrystalline silicon (nc-Si:H) thin-film transistors (TFTs) fabricated at 260 °C. This is made possible simply using Cr drain–source Schottky contacts with high-purity and high-crystallinity nc-Si:H channel layer, which creates highly conductive Cr silicided contacts, reducing both hole and electron injection barriers. The p-channel nc-Si:H TFTs show a field-effect hole mobility (μhFE) of 25 cm2 V−1 s−1, a threshold voltage (VT) of −3.8 V, a subthreshold slope (S) of 0.25 V/dec, and an ON/OFF current ratio of more than 106, while the n-channel nc-Si:H TFTs show a field-effect electron mobility (μeFE) of 150 cm2 V−1 s−1, a VT of 2 V, a S of 0.3 V/dec, and an ON/OFF current of more than 107. The TFT performance reported here offers promise for low-temperature complementary metal oxide semiconductor (CMOS) circuit integration.