Switching behavior of microcrystalline silicon deposited by hot-wire chemical vapor deposition

Abstract

We study current-induced changes in electrical and structural properties of a p-type microcrystalline silicon (μc-Si) films sandwiched between two metal contacts. After switching, the resistance decreases from above 1MΩ to below 1kΩ. The voltage–current characteristics show a saturated voltage region where irreversible changes occur gradually. In this region, transient temperature measurements show that film temperature rises considerably. The resistance of the switched state depends strongly on device area, suggesting that structural changes responsible for switching involve a large fraction of the device area. Micro-Raman studies show that film crystallinity increases during switching. This increase in crystallinity may indicate that the electrical switching process involves the formation of percolation paths through an amorphous incubation layer formed during film growth. This switching mechanism is quite different from the metallic filament formation observed in amorphous silicon switches.