States of hydrogen in crystalline semiconductors

Abstract

The stable configurations of hydrogen in undoped, and in r t and ptype semiconductors are reviewed. We compare the experimentally determined configurations with theoretical predictions made by a variety of calculational methods. In undoped Si, as an example, hydrogen appears to occupy a near-bond-centered (BC) site between neighbouring Si atoms with a secondary local minimum in energy occurring at a tetrahedral interstitial (T) site. In B-doped, ptype Si, hydrogen at a near BC site accounts for acceptor passivation. By contrast in n-type Si, hydrogen at the antibonding (AB) position appears to be responsible for donor passivation. The possible configurations in other semiconductors (Ge, GaAs and AIGaAs) are also summarized.