Planar guarded avalanche diodes in InP fabricated by ion implantation

Planar guarded avalanche diodes in InP have been fabricated using a double-ion-implantation technique. Silicon was selectively implanted into an n-type epitaxial layer to increase the concentration portion of the diode, and beryllium was implanted to form the p-n junction. When appropriately reverse biased, these diodes exhibited uniform avalanche photocurrent gain in the central portion, where the electric field is maximum. With a 1-kΩ load, photoresponse gains as high as 20 were measured, although values of 6 to 8 were more typical. At present, the external photoresponse gain with a fixed load is limited by the shunting effect of the diode’s differential resistance.