US 4,391,524 AGranted

Method for determining the quality of light scattering material

AssigneeRCA Corporation

InventorsEdgar F. Steigmeier, Heinrich Auderset

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Abstract

A method of determining the crystalline quality of heteroepitaxial silicon material, particularly silicon-on-sapphire (SOS) and of homoepitaxial silicon material which uses the light scattering is disclosed. The material is exposed to a beam of light of a selected wavelength, and scattered light having an intensity above a threshold is detected to provide a signal which is used to control the intensity of a display beam of a visual display device. The threshold is varied to thereby vary the display beam intensity so as to provide the minimum intensity of display beam which yields a full display. The value of the thusly adjusted threshold intensity is used as a direct measure of the quality of the material.

Claims12

Dependent claims

The method for determining the quality of a material having a property of absorbing light to a given penetration depth comprising the steps of:

(a) exposing one or more regions of said material to a beam of light of a selected wavelength;
(b) detecting scattered light having an intensity greater than a threshold intensity from the exposed material to provide an electrical signal proportional to the intensity of detected scattered light above said threshold intensity;
(c) applying the electrical signal to a visual display device to control the intensity of a display beam of the device;
and
(d) varying said threshold intensity to thereby vary the intensity of the display beam so as to provide the minimum intensity of display beam which yields a full display of the exposed material, wherein the value of the threshold intensity is a direct measure of the crystalline quality of the material.

2 more elements

Dependencies are inferred from the claim text.