Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Patent
1993-02-02
1995-07-04
Nguyen, Vinh
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
324767, 324750, G01R 3126
Patent
active
054303869
ABSTRACT:
Method and its device for evaluating semiconductor wafers that evaluates semiconductor wafers by estimating the dopant level which is equivalent to the critical value at which the excess minority carrier injection density reaches the high injection state, and that measures the minority carrier lifetime at a low-injection-state exposure condition adapted to said dopant level. Excitation light (emitted by excitation light generator 4) is emitted onto a semiconductor wafer 2 at varying exposure conditions as imposed by an exposure condition controller 9. Detector 6 detects the change in the level of reflected radiation from microwaves emitted by microwave generator 5 onto the wafer 2. The dopant level in the semiconductor wafer 2 is estimated by estimation circuit 10' based on the change in the exposure conditions and the change in the minority carrier lifetime as determined by the change in the microwave level. The minority carrier lifetime is measured by measurement circuit 12 at the exposure condition adapted to said dopant level as detected by exposure condition detection circuit 11. This structure makes possible the estimation of the dopant level in the semiconductor wafer while obtaining the lifetime based on Shockley-Read-Hall statistics, and is thus highly qualified for evaluating the semiconductor wafer 2.
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Friedt Jean
Fujihira Chiyo
Hashizume Hidehisa
Hirose Masatake
Morin Michel
L'Air Liquide, Societe Anonyme Pour L'Etude Et L'Exploitation De
Leo Corporation
Nguyen Vinh
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