Characterization of near-surface traps in semiconductors: GaN

We present a simple a criterion, based on deep-level transient spectroscopy peak heights S(V-r) at two or more values of reverse bias V-r, to unequivo cally determine whether or not a particular semiconductor trap is of bulk o r near-surface nature. Moreover, we present an expression for S(V-r) with f itting parameters phi (B), the Schottky barrier height; delta, the trap pen etration depth; and N-T, the trap density. Application of the method to a t hick, high-quality, epitaxial GaN layer, reveals two common traps which pen etrate only 2700 +/- 300 A into the layer. (C) 2001 American Institute of P hysics.