Accession Number : ADD007903

Title :   Contactless Resistivity Measurement Method.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE ARMY WASHINGTON DC

Personal Author(s) : Iafrate,Gerald J ; Ballato,Arthur

Report Date : 27 Oct 1980

Pagination or Media Count : 36

Abstract : This invention relates to methods and apparatus for contactless, non-destructiveresistivity measurements on semiconducting crystalline material, for example, gallium arsenide. The material to be tested is formed into a disc which is supported within an air gap. The holder for the disc is such as to support the disc only about its outer edges; thus, the disc is free to vibrate piezoelectrically. A measuring circuit connected to the electrodes, which establish the air gap, applies an alternating electric field in the air gap which causes the crystal to vibrate. By adjusting the frequency of excitation, resonance may be established in the crystal and by comparing the current drawn through the air gap with graphs previously established for material of the type under test, the resistivity of the disc can be determined. (Author)

Descriptors :   *Patent applications, *Electrical resistance, *Electrical measurement, *Electric contacts, Nondestructive testing, Semiconductors, Crystals, Electric fields, Coupling circuits, Gallium arsenides, Piezoelectric effect, Piezoelectric materials, Energy gaps, Graphs, Disks

Subject Categories : Electrical and Electronic Equipment
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE