The effects of the nonabrupt depletion edge on deep-trap profiles determined by deep-level transient spectroscopy

Abstract
The effects of the nonabrupt depletion edge (the Debye tail) on the trap concentrations obtained by deep-level transient spectroscopy are discussed. In depth profiling of traps it is shown that a dramatic drop in the apparent deep-trap concentration is obtained near the edge of the total depth probed. This is an artifact of the measurement and is a consequence of the Debye tail in the depletion edge. It is shown that experimentally one can avoid this problem by using sufficiently large reverse biases and forward filling pulses to determine the deep-trap concentration in any particular region of the semiconductor.