Analysis of MOS phototransistor operation by 2-D simulation using cylindrical coordinates

We have developed a new device simulator for a charge modulation device (CMD). This simulator has two characteristic features; adopting cylindrical coordinates and transient analysis including carrier generation by light. By this simulator, non-steady state I-V characteristics and phototransistor operation of a CMD are physically interpreted. Furthermore, the relationship between these characteristics and the structural parameters are analyzed, and it is shown to be possible to scale down a CMD without decreasing sensitivity.