Hole Diffusion Lengths in VPE GaAs and GaAs0.6 P 0.4 Treated with Transition Metals

Abstract

The effects of several metals on L, in GaAs and GaAs0.6Po.4 have been evaluated. Diffusion of Co at 700~ for 5 rain into VPE n-GaAs0.6Po.4 is found to produce a considerable reduction of Lp. Lesser degradation is caused by Ni, whereas Cu, Cd, and Zn improve L,. In VPE n-GaAs, diffusions of Co, Cu, W, and Cd improve Lp. These improvements are believed to be caused by gettering of lifetime killing deep impurities, such as Co and Ni, by shallow diffused junctions. The metals that degrade LD appear to be ones with small tetrahedral covalent radii.

Semiconductor Electrodes: LV. Differential Photocurrent Determination of Absorption Coefficient and Diffusion Length in Photoelectrochemical Cells

“…Further, ions adventiously incorporated into the lattice can also reduce the lifetime, ~. For example, Partin et al (33) have shown that diffusion of cobalt into VPE n-GaA~0.6P0.4 produced a considerable reduction of the diffusion length. Although L has been shown to be a function of doping density (15), the values of L obtained here (~0.1 ~m) are at the lower end of the range of values reported for similar doping densities.…”

Minority Carrier Diffusion Length EBIC Measurements in Cadmium Telluride

“…Alternatively a very thin highconcentration surface skin could develop that might have the effect of gettering recombination defects from the bulk. Defect gettering appears to occur in GaAs as a result of sub-monolayer surface contamination from various etches used, even though the chemicals are of semiconductor grade purity for Si processing (13)(14)(15). Further experiments to establish whether similar effects occur for CdTe need to be done.…”

“…An hour or so before insertion in the scanning electron microscope (JSM-35) the specimens to be measured were cleaved across the Schottky barrier, mounted in a T05 header, and checked for leakage currents of less than 10-9A at a reverse voltage of 1V. The diffusion length measurement procedure was then as described by Sekela et al (10) or others (11)(12)(13)(14) with about 0.1V or less reverse voltage applied to the diode. Most of the measurements were made at a beam voltage of 25 keV and a beam current in the low 10-10A.…”

Electrochemically Deposited Copper Schottky Contacts on n-Type GaAs for Electron-Beam-Induced Current Measurements

“…Of course, for determining reliable L values, any heat treatment must be avoided since Cu is a very fast diffuser in GaAs and might affect L , , considerably. For example, Cu diffusion into VPE n-GaAs was found to double L due to gettering of lifetime-killing deep impurities by an inverted region [36].…”