Hole and electron field-effect mobilities in nanocrystalline silicon deposited at 150 °C

Abstract

Field-effect structures were made from nanocrystalline silicon (nc-Si:H) deposited at a substrate temperature of 150 °C by plasma-enhanced chemical vapor deposition excited at 80 MHz. The nc-Si:H channel layer was grown on top of a separate nc-Si:H buffer and seed layer that serves to develop the crystalline structure. Staggering the contacts and the gate ensures that mobilities are measured precisely in the last-to-grow nc-Si:H layer. The hole mobility in saturation reaches 0.06–0.2 cm2 V−1 s−1 and the electron mobility ∼12 cm2 V−1 s−1. These results suggest that large-area circuits of complementary p- and n-channel devices can be made from nc-Si:H deposited on low-temperature substrates.