Browse Prior Art Database

Detecting Conductivity Type in Semiconductor Analysis

IP.com Disclosure Number: IPCOM000074756D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Poponiak, MR: AUTHOR [+2]

Abstract

This technique is used to identify P or N conductivity type by interpretation of data obtained with a spreading resistance probe.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Detecting Conductivity Type in Semiconductor Analysis

This technique is used to identify P or N conductivity type by interpretation of data obtained with a spreading resistance probe.

The conductivity of bulk material can be tested by conventional techniques such as hot-point probe, cold-point probe, and rectifying probe. However, none of these techniques can be used to detect the conductivity type of multilayer epitaxial or diffusion structure.

In a spreading resistance probe, two spaced contacts are used to introduce a flow of current in the semiconductor. A voltage measured between one of the contacts and the spreading resistance probe (a third probe) can be used to determine the amount of impurity in the semiconductor in the vicinity of the probe. In this technique the nature of the impurity, that is whether P or N type, can be detected. When the probe makes contact with a semiconductor, the forward voltage drop is less than the reverse voltage drop. For N and P type materials the forward and reverse voltage drops are just opposite to each other. From the different voltage drop readings the type of material can be determined. Basically, the current is reversed in the current probes and the change in voltage drop is noted. When the probe crosses the PN junction the forward and reverse voltage drop readings switch. This is an added advantage to the spreading resistance probe, because it determines the exact location of the junction.

1