HIGH-SPEED LATERAL POLYSILICON PHOTODIODES

A high-performance latera p-n photodiode in LPCVD polysilicon has been successfully fabricated and characterized. The device is shown to hav e a response time of 30 ps, i.e. a 3 dB cut-off frequency of 5.3 GHz, which we believe is the fastest speed reported in polysilicon. The mea sured device speed is analysed quantitatively on the basis of the reco mbination-dominated-response model. In so doing, an analytic expressio n for the impulse response function of such devices is given here for the first time. The general features of the device and its possible ap plications in optoelectronic integrated circuits are also discussed.