Cr/p-HgCdTe (x = 0.28, 1.0) contact resistance and I-V characteristics in the LTLM configuration

TL;DR

This study investigates the contact resistance and I-V behavior of Cr/p-HgCdTe and related heterointerfaces using the LTLM method, revealing linear I-V characteristics and factors affecting contact resistance at different temperatures.

Contribution

It provides new insights into the contact resistance mechanisms of Cr-based contacts on HgCdTe and CdTe, using the LTLM method and considering the role of metal-induced gap states.

Findings

Linear I-V characteristics at 77K and 300K.

High contact resistance linked to Cr-oxide formation and element diffusion.

Absence of intermediate dielectric layers at interfaces.

Abstract

The specific contact resistance $\rho_c$ of Cr/p-Hg$_{0.72}$Cd$_{0.28}$Te and Cr/p-CdTe/p-Hg$_{0.72}$Cd$_{0.28}$Te heterointerfaces, which were formed by deposition of Cr films at room temperatures on the surfaces of semiconductors, was studied by the Linear Transmission Line Model (LTLM) method. It was observed linear or close to linear behavior of current-voltage (I-V) characteristics at temperatures T = 77 and 300 K. It was assumed that relatively large specific contact resistance $\rho_c$ perhaps is mainly connected with the formation of Cr-oxides and the elements diffusion into Cr layers from the semiconductors under consideration. No intermediate dielectric layer, separating Cr from Hg0.72Cd0.28Te or CdTe layers was observed. It was accepted that the MIGS (metal-induced gap states) model in the semiconductor can be considered to describe the mechanism of current transport through the Cr/p-CdTe/p-Hg$_{0.72}$Cd$_{0.28}$Te and Cd/p-Hg$_{0.72}$Cd$_{0.28}$Te interfaces (Schottky barriers - SBs). The linear or almost linear I-V-characteristics in the LTLM configuration observed can be explained by taking into account the series resistance of bulk semiconductor substrate and low resistance of large area SBs.