Effects of grain boundaries on TFTs formed by high-temperature MILC

Abstract

The effects of grain boundaries on the performance of super TFTs formed by MILC are studied. The existence of grain boundaries in the channel region will cause subthreshold hump, early punchthrough or device degradation, depending on the direction of the grain boundaries. The probability for the channel region of a TFT to cover multiple grains decrease significantly when the device is scaled down, thus resulting in better device performance and higher uniformity. A novel method to measure the grain dimension by using boundaries oxide as a etching mask has also been developed.