A CMOS imager hybridized to an avalanche multiplied film

Abstract

A highly sensitive solid-state imager has been made by connecting an avalanche multiplier film to a MOS readout circuit through microbump electrodes. Optimization of the vapor-deposition conditions for the indium bump material made it possible for microbumps 5 /spl mu/m in diameter and 5 /spl mu/m in height to be formed into a 2/3-in matrix array of 380 000 pixels. A prototype imager was constructed with a 0.5-/spl mu/m thick avalanche photoconductive film. Clear avalanche multiplication of about ten times was observed at an applied voltage of 75 V. The imager had a good resolution and no recognizable afterimages.