Research On Dry Etch Technology Of HgCdTe Photoconductor

HgCdTe is the most widely used material for IR detectors' fabricating,basically because its superior photon-electronic characters.As the fabrication process is very simple and cost can be controlled in a low level,HgCdTe IR photo-conductive detectors still receive widespread applications in many detection domains.With the promoted demands for IR detectors' performance claimed by modern detecting systems,fabrication process is faced with more and more difficulties.For HgCdTe IR PC detectors,this process can be split into several parts: thickness reduction,surface passivation,micro mesa isolation,electrode making,etc.Ion beam dry etch is the technology used for detectors' micro mesa isolation,compared with traditional wet etch method,dry etch method has the advantage that it is anisotropic.Ion beams used for etching have certain amounts of energy,that would induce some etching damage as HgCdTe material is being processed,and will also risen the temperature of HgCdTe material.These causes would impact material's photon-electronic characters.So it is necessary to make an assessment about the influence imposed by dry etch upon HgCdTe material's electronic performance.This dissertation consists:Protected HgCdTe material with masking,studying temperature-rising effect and the corresponding HgCdTe performance caused by different dry etching conditions,thus made a comment on the etching thermal effect and explained the abnormal result of previous detector fabrication process.Developed a kind of compound masking suitable for extreme-low temperature dry etching,replacing photo-resist which would crack in that environment.Completed the fabrication process of HgCdTe IR PC detectors in extreme-low temperature for the first time,and compared the testing result with those obtained in room temperature processing.Analyzed the contents of epoxy and its chemical properties,found a way to remove epoxy,which would be helpful in newly designed detectors' processing.Problems which should be taken care of are also listed.