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Determination of Impurity Profiles in Semiconductors

IP.com Disclosure Number: IPCOM000092643D
Original Publication Date: 1966-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Gereth, R: AUTHOR

Abstract

This publication relates to a technique for the determination of impurity profiles in semiconductors. The corrosion potential method, called CPM, provides a direct and unique way of measuring impurity profiles in semiconductors.

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Determination of Impurity Profiles in Semiconductors

This publication relates to a technique for the determination of impurity profiles in semiconductors. The corrosion potential method, called CPM, provides a direct and unique way of measuring impurity profiles in semiconductors.

Established techniques for determining impurity profiles involve two separate operations, that is, sectioning of sample under test and actual measuring of impurity content. The CPM circumvents this lengthy approach. It allows the determination of impurity profiles in a single operation.

The apparatus for carrying out the CPM is shown in drawing A. The semiconductor material to be analyzed is exposed to a corroding medium in an electrolytic cell. The latter consists of a Ge electrode 1 and a saturated calomel reference electrode 2, both immersed in an appropriate electroylyte 3. For the system used, electrolyte 3 is composed of 0.1 mK(3) >Fe (CN)(6)|, 0.1 n NaOH, and 1.0 n NaNO(3). The corrosion potential UK between semiconductor 1 and electrolyte 2 is a function of the impurity content of semiconductor 1. UK is monitored on a strip chart recorder 4 as the semiconductor surface is etched away at a uniform rate of 0.1 micron/MIN. Auxiliary Pt electrode 5 permits the measurement and control of the corrosion rate and thus the establishment of reproducible results. Black wax, SiO(2) or photoresist masks 6 or both can be employed to delineate a well-defined surface area 7 on electrode 1. It...