Effects of inductively coupled plasma oxidation on the properties of polycrystalline silicon films and thin film transistors

Abstract

We investigated the effects of inductively coupled plasma (ICP) oxidation on the properties of polycrystalline silicon (poly-Si) films and thin film transistors (TFTs). The ICP oxidation in oxygen plasma passivated the dangling bonds in the poly-Si films, not by oxygen incorporation but by hydrogen incorporation; but the incorporated hydrogen diffused out during the TFT fabrication, so that the effect of the dangling bond passivation was not obtained in the TFT. The ICP oxidation did not remove the intragranular defects such as microtwins and stacking faults, but it reduced the interface trap density and also improved the performance of the poly-Si TFT. The field effect mobility of TFT with an ICP oxide and low-pressure chemical vapor deposited (LPCVD) oxide double layer was 30.6 cm2/V s, while that of TFT with only a LPCVD oxide was 17.2 cm2/V s.