Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
2005-07-05
2005-07-05
Ramirez, Nestor (Department: 2829)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S1540PB
Reexamination Certificate
active
06914442
ABSTRACT:
The present invention is to provide a method for measuring resistivity of a semiconductor wafer by the use of an AC-SPV method even though the wafer is left in a depletion state or a weak inversion state. The present invention is the method for measuring resistivity of a semiconductor wafer by the use of a surface photo voltage method, and comprises the steps of: (a) measuring a surface photo voltage value in both regions of a low frequency region in which a constant surface photo voltage value is obtained irrespective of a frequency of incident light on a semiconductor wafer to be measured and in a high frequency region in which the surface photo voltage value inversely proportional to the frequency of the incident light is obtained and calculating a cut-off frequency fcfrom the obtained measured value; (b) calculating a depletion layer width Wdfrom capacitance Cdpcalculated from the surface photo voltage value in the high frequency region; (c) calculating majority carrier conductance gmjfrom the cut-off frequency fcand the capacitance Cdp; and (d) calculating surface potential Usand Fermi potential UFfrom the cut-off frequency fc, the capacitance Cdp, the depletion layer width Wd, and the majority carrier conductance gmj.
REFERENCES:
patent: 4051437 (1977-09-01), Lile et al.
patent: 5140272 (1992-08-01), Nishimatsu et al.
Nguyen Tung X.
Rader & Fishman & Grauer, PLLC
Ramirez Nestor
Shin-Etsu Handotai & Co., Ltd.
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