GaAs MSM photodetectors with recessed anode and/or cathode

摘要

The GaAs metal-semiconductor-metal photodetectors (MSM-PDs) withnrecessed electrodes have been systematically characterized. The recessedncathode results in effective collection of the speed-limiting holes duento both a strengthened electric field and a shortened transit pathnaround the absorption region while the recessed anode gives nonsignificant change on the electric field distribution, as evidenced bynthe two dimensional simulation. The experimental results show that thenMSM-PDs having the recessed-cathode structure, compared with thenconventional one, exhibit a substantial improvement on the speed, peaknamplitude, and capacitance, especially at low-bias operation. The fallntime of the temporal response approaches its saturation value of aboutn10 ps at a bias voltage as low as 3 V on the 50 Μm×50 Μmndetector with a finger width and spacing of 2 Μm