Depth Profiling of Electronic Transport Parameters in n-on-p Boron-Ion-Implanted Vacancy-Doped HgCdTe

Abstract

We report results of a detailed study of electronic transport in n-on-p junctions formed by 150-keV boron-ion implantation in vacancy-doped p-type Hg_0.769Cd_0.231Te without postimplantation thermal annealing. A mobility spectrum analysis methodology in conjunction with a wet chemical etching-based surface removal approach has been employed to depth profile the transport characteristics of the samples. In the as-implanted samples, three distinct electron species were detected which are shown to be associated with (a) low-mobility electrons in the top 220-nm surface-damaged layer (E ₁: μ _80K = 2940 cm²/Vs), (b) the B-ion implantation region in the top 500-nm region (E ₂: μ _80K = 7490 cm²/Vs), and (c) high-mobility electrons in the n-to-p transition region at a depth of 600 nm to 700 nm (E ₃: μ _80K = 25,640 cm²/Vs). Due to the maximum magnetic field employed (2 T), hole carriers from the underlying vacancy-doped p-type region were detected only after the removal of the top 220 nm of the profiled sample (μ _80K = 126 cm²/Vs), revealing fully p-type character 800 nm below the original sample surface. A comparison of the extracted E ₂ electron concentration and calculated B-impurity profile suggests that the n-type region is due primarily to near-surface implantation-induced lattice damage.