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Browse Prior Art Database

Technique for Delineating P/P/+/ Interfaces in Germanium

IP.com Disclosure Number: IPCOM000091063D
Original Publication Date: 1969-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Cowher, ME: AUTHOR

Abstract

This technique is for delineating P/P/+/ interfaces in germanium. The P/P/+/ interface has been extremely difficult if not impossible to delineate. Delineation of interfaces is necessary to obtain accurate measurement of epitaxial thickness, observe P/P/+/ interfaces for quality comparison and control, and investigate impurity concentration gradients.

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Technique for Delineating P/P/+/ Interfaces in Germanium

This technique is for delineating P/P/+/ interfaces in germanium. The P/P/+/ interface has been extremely difficult if not impossible to delineate. Delineation of interfaces is necessary to obtain accurate measurement of epitaxial thickness, observe P/P/+/ interfaces for quality comparison and control, and investigate impurity concentration gradients.

After mounting and polishing a sample of germanium containing a P/P/+/ interface, the following etching and staining procedure is carried out. The etching step is required to remove enough damage to allow a staining solution to work properly. All of the sample, except the area in question, is protected with black wax or other suitable protective material. The sample is etched with a 10:1:1 solution of H(2)O:HF:H(2)O(2) for 15 seconds or longer. Then the sample is rinsed in distilled water and blown dry with air.

A stain consisting of a solution of 0.5 cc of CuSO(4) saturated solution 2.5 cc HF 48%, and 97.0 cc H(2)O is applied under strong light until the interface is clear. The sample is then rinsed in distilled water and blown dry with air. The resulting sample shows that P stains more than P/+/. In some instances, the P/+/ region does not even stain.

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