Recent Improvements in Dry Etching of Hg_1−xCd_xTe by CH₄ Based Electron Cyclotron Resonance Plasmas

Abstract

Significant improvements of a previously reported etching process [1] for Hg1−xCdxTe have been achieved with respect to etch rate, surface morphology and surface stoichiometry by optimization of the process parameters. The gas phase and surface reactions driving the etching process have been analyzed by combined optical and electrical characterization of the plasma and surface analyses of the samples. A reaction scheme is suggested which allows to model and upscale the process in a consistent manner.

Influence of Cadmium Composition on CH4–H2-Based Inductively Coupled Plasma Etching of Hg1−x Cd x Te

“…Such an etch rate increase correlates well with our results obtained at lower ion energy. Also, these data and the interpretation described above suggest that the temperature independence of the etch rate in the range from -25°C to 80°C observed by another group 16 could be related to conditions in which the etching mechanism is more physical than chemical.…”

“…Indeed, some studies report an increase of etch rate when the temperature is increased from 50°C to 90°C, 15 whereas others state that substrate temperature has no effect in the range from À25°C to 80°C. 16 This is the reason why we have chosen to study the influence of temperature on the MCT etching process.…”

Inductively coupled plasma etching of HgCdTe using a CH4-based mixture

“…[7][8][9][10][11][12][13][14] However, inductively coupled plasma (ICP) etching may be more suitable for production, mainly because of its better uniformity and its lower cost, due to its simple design, [15][16][17] in contrast to ECR systems, which include complex components, such as microwave tuning networks and microwave guides. There are surprisingly few results in the literature concerning ICP etching of HgCdTe.…”