Performance of InGaAs photodetectors: lateral p-n and p-n-p diodes

Lateral InGaAs p-n and p-n-p photodiodes were fabricated by area-selective diffusion of Zn through Al
₂
O
₃
masks. Low dark current densities and a carrier transit-time limited frequency behavior were found. P-n diodes show a 3 dB bandwidth of 19 GHz for an electrode separation of 4 μm. High optical gain was obtained with the lateral p-n-p structure leading to a responsivity of 6-8 A/W in the wavelength range between 1.0 and 1.6 μm, which is considerably more than with the p-n device and conventional MSM detectors.