LONG-WAVELENGTH INGAASP AVALANCHE PHOTO-DIODES

InGaAsP avalanche photodiodes have been fabricated with uniform high-speed gains of 40 and quantum efficiencies up to 63% at 1.05 μm. At high gains increased leakage current leads to excessive shot noise. Noise measurements indicate that the increased leakage current arises from a uniformly multiplied but increasing value of the primary (i.e., premultiplication) leakage current. The increase in leakage current is thought to be due to surface effects. The size of the leakage current is shown to lead to a prediction of gain saturation in approximate agreement with the observed maximum gain.