Surface treatment and protection method for cadmium zinc telluride crystals
AssigneeSandia National Laboratories
InventorsGomez W. Wright, Ralph B. James, Arnold Burger, Douglas A. Chinn
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Abstract
A method for treatment of the surface of a CdZnTe (CZT) crystal that provides a native dielectric coating to reduce surface leakage currents and thereby, improve the resolution of instruments incorporating detectors using CZT crystals. A two step process is disclosed, etching the surface of a CZT crystal with a solution of the conventional bromine/methanol etch treatment, and after attachment of electrical contacts, passivating the CZT crystal surface with a solution of 10 w/o NH4F and 10 w/o H2O2 in water.
Claims16
A method for forming a detector sensitive to ionizing radiation, comprising the steps of:
- a) etching a surface of a CdZnTe crystal with a solution of bromine in methanol;
- b) growing a dielectric layer on said etched surface forming thereby a passivated surface;
- c) applying a photoresist layer onto said dielectric layer;
- d) exposing a portion of said photoresist using electromagnetic radiation and a lithography means;
- e) developing and removing said exposed portion thereby creating an image pattern in said photoresist and exposing a corresponding portion of said passivated surface;
- f) removing said corresponding portion of said passivating surface and thereby replicating said image onto said CdZnTe crystal surface;
- g) depositing a metal conductor onto said surface image thereby forming an electrode on said exposed CdZnTe crystal surface;
- and
- h) removing the remaining photoresist layer.
Dependencies are inferred from the claim text.