A planar InGaAs/InP avalanche photodiode having a separated absorption and multiplication (SAM) structure has been designed and fabricated making use of silicon ion implantation as the n-type impurity source for formation of the high-field multiplying region followed by epitaxial regrowth of an InP capping layer into which the junction is diffused. Vapor-phase epitaxial techniques have been used for growth of the various layers of the structure. The basic structure of the device is shown in Fig. 1. Since the successful operation of a SAM APD is somewhat critically dependent on the detailed field profile, the doping concentration of n-type carriers in the InP multiplying region is also critical. In particular, an aerial concentration of ~2 × 1012/cm2 is required to achieve the desired field conditions in the diode.
© 1988 Optical Society of AmericaPDF Article