Apparatus for measuring minority carrier lifetimes in semiconductor materials

Patent · Tue Jul 27 00:00:00 EDT 1999

OSTI ID:6438346

Ahrenkiel, R K

An apparatus for determining the minority carrier lifetime of a semiconductor sample includes a positioner for moving the sample relative to a coil. The coil is connected to a bridge circuit such that the impedance of one arm of the bridge circuit is varied as sample is positioned relative to the coil. The sample is positioned relative to the coil such that any change in the photoconductance of the sample created by illumination of the sample creates a linearly related change in the input impedance of the bridge circuit. In addition, the apparatus is calibrated to work at a fixed frequency so that the apparatus maintains a consistently high sensitivity and high linearly for samples of different sizes, shapes, and material properties. When a light source illuminates the sample, the impedance of the bridge circuit is altered as excess carriers are generated in the sample, thereby producing a measurable signal indicative of the minority carrier lifetimes or recombination rates of the sample. 17 figs.

• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC36-83CH10093
• Assignee: Midwest Research Inst., Kansas City, MO (United States)
• Patent Number(s): US 5929652; A
• Application Number: PPN: US 8-922003
• OSTI ID: 6438346
• Resource Relation: Patent File Date: 2 Sep 1997
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
CARRIER LIFETIME
DESIGN
MATERIALS TESTING
MEASURING INSTRUMENTS
MEASURING METHODS
PHOTOCONDUCTIVITY
POSITIONING
SAMPLE HOLDERS
SEMICONDUCTOR MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
LIFETIME
MATERIALS
PHYSICAL PROPERTIES
TESTING
360606* - Other Materials- Physical Properties- (1992-)
420500 - Engineering- Materials Testing