Barrier layer induced channeling effect of As ion implantation in HgCdTe and its influences on electrical properties of p-n junctions.

The HgCdTe layers (xCd∼0.285 and 0.225) were grown by molecular beam epitaxy and liquid phase epitaxy, respectively, followed by the deposition of CdTe and ZnS films as barrier layers by thermal evaporation. Then, the p-on-n photodiodes were fabricated by AS ion implantation, Hg overpressure annealing, passivation, and metallization. The secondary ion mass spectrometry and transmission electron microscopy results indicate that the evaporated CdTe layer with a column structure induces the channeling effect of As ion implantation causing the device performance degradation. This effect could be suppressed by depositing a CdTe film with a layered structure through E-beam evaporation. Finally, the current–voltage (I–V) and capacitance–voltage (C–V) characteristics of these p–n junctions were estimated and analyzed.