Laser gettering of structural-impurity defects in the contacts of metal-intrinsic CdTe with a Schottky barrier

The influence of surface laser treatment on structural properties of metal-intrinsic CdTe contacts was investigated by metallographic method and scanning electronic microscopy techniques. At critical intensities of pulse laser irradiation on the metal-CdTe boundary re-structuring of structurally impurity defects in a solid state occurs. A defect system of large grains of single crystalline CdTe is formed. Separate clusters were ordered over a long range and formed their own “crystalline sublattice”, probably, of trimetric configuration. A diameter of the cluster in nodes of such a lattice equalled 1-3 μm, while distance between clusters was of about 10-15 μm. As radiation dose was increased the clusters acted as getters of dot defects. At optimal modes of laser irradiation their sizes increased in 2-3 times, consequently leading to decrease in concentration of deep levels in the semiconductor. As has shown investigation of the I-V and C-V characteristics such processes caused reduction of GR component of a current, promoting field charge transfer mechanisms in contacts with a Schottky barrier.