Optimization of micro-bump electrodes for HARP solid-state imager

Abstract

A high-sensitive solid-state imager has been studied by connecting an avalanche multiplier film to MOS readout circuit via micro-bump electrodes. Optimization of the substrate temperature on Indium verpor-deposition made it possible for micro-bumps of 4μm width and 5μm height to be formed into a 2/3-inch matrix array of 380k pixels. In a prototype imager, clear avalanche multiplication of about ten times was observed. The imager has a good resolution and no recognizable after-images.