Development of radiation-hard preamplifier chip for BELLE SVD

We have studied the radiation hardness of preamplifier VLSI and MOS transistors fabricated with the rapid thermal nitridation process and low temperature grown thin (15 nm) oxide. Tungsten-silicide is used as a gate material. These processes are used to fabricate front-end preamplifier chips for the BELLE silicon vertex detector. Significant improvement in radiation hardness has been observed for some transistors.