Alok K Berry

US Patent:

53791096, Jan 3, 1995

Filed:

Jun 17, 1992

Appl. No.:

7/899977

Inventors:

D. Kurt Gaskill - Alexandria VA
Nicholas Bottka - Burke VA
Alok K. Berry - Burke VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01N 2155
G01N 2184

US Classification:

356445

Abstract:

An apparatus for non-destructively measuring resistivity of a semiconductor, such as InP, comprises light sources for illuminating a preselected portion of the semiconductor with first and second light beams, each of a preselected single wavelength, the first light beam operating to excite the semiconductor by photo injecting carriers, and the second light beam bombarding the local portion of the semiconductor with a preselected photon energy. The apparatus measures a fractional change in reflectance of the second light beam responsive to the first light beam, and records this fractional change in reflectance for various values of photon energy of the second light beam, to generate a photoreflectance line-shape. The photoreflectance line-shape is used to calculate a photoreflectance line-shape phase angle, which is used to determine the resistivity of the preselected portion of the semiconductor.