DRY-ETCHING OF HG1-XCDXTE USING CH4 H-2/AR/N-2 ELECTRON-CYCLOTRON-RESONANCE PLASMAS/

An approach is presented which eliminates the problems caused by hydro carbon polymer deposition during etching Hg1-xGdxTe with CH4/H-2 based plasmas. We find that the addition of N-2 to the plasma inhibits poly mer deposition in the chamber and an the sample. We speculate that ato mic nitrogen formed from N, in the plasma has several beneficial effec ts: the elimination of polymer precursors, the reduction of the atomic hydrogen concentration, and a potential increase of methyl radical co ncentration. Evidence for the reaction between the nitrogen and the po lymer precursors is presented. It is also demonstrated that the additi on of N-2 to CH4/H-2 based electron cyclotron resonance (ECR) plasmas used to etch HgCdTe eliminates the roughness normally formed during et ching and results in a steadier etch rate.