Doping of III–V compound semiconductors by ion implantation

Abstract

The use of ion implantation to dope III–V compound semiconductors is growing in importance because it can be applied in the manufacture of discrete devices such as LEDs, lasers and FETs and increasingly, in the production of both linear and digital integrated circuits. As in silicon technology, the advantages of implantation include good control over depth profiles and sheet carrier concentration, good reproducibility, and good uniformity. With compounds, however, there is probably a greater need to know the depth variation of the carrier concentration, as well as the percentage electrical activation of the dopant atoms and the measurement of profiles is discussed together with the problems of annealing. Dissociation and loss ofthe volatile component during annealing has to be avoided, and therefore various annealing methods have been tried in order to establish the best technique for particular applications. Recent progress in these annealing studies are discussed. The effects of the substrate on the resultant carrier concentration profile is also reviewed since the redistribution of impurities due to damage and subsequent heat treatment can vary considerably with starting material, annealing schedule, ion, dose, dose rate, etc., and is thus an important factor in making devices. The production of n-type, p-type and semi-insulating layers is reviewed and a brief summary given of recent device applications.