Patent
Method and apparatus for characterizing a specimen of semiconductor material
TLDR
In this paper, a method and apparatus for determining the doping concentration profile of a sample of semiconductor material is described, where the sample is positioned between a pair of electrodes, the specimen being disposed on one of the electrodes and being spaced form the other electrode by a nonconductive medium.Abstract:
A method and apparatus are provided for determining the doping concentration profile of a specimen of semiconductor material. The specimen is positioned between a pair of electrodes, the specimen being disposed on one of the electrodes and being spaced form the other electrode by a nonconductive medium. In one implementation of the invention the nonconductive medium is air. A region of the surface of the specimen is illuminated with a beam of light of wavelengths shorter than that corresponding to the energy gap of the semiconductor material and which is intensity modulated at a predetermined frequency. A variable DC bias voltage is applied between the pair of electrodes, the variable DC bias voltage varying between that corresponding to accumulation and that corresponding to deep depletion for the specimen. The intensity of the light beam is low enough and the speed at which the DC bias voltage is varied is fast enough such that no inversion layer is formed at the surface of the specimen. A signal is also provided corresponding to the total capacitance between the two electrodes during the DC bias voltage sweep. A signal is provided representing the ac photocurrent induced at the region of the specimen illuminated by the light beam. The intensity of the light beam and frequency of modulation of the light beam are selected such that the ac photocurrent is nearly proportional to the intensity of the light beam. The doping concentration profile is then determined using the ac photocurrent, the total capacitance and the DC bias voltage. The apparatus includes a sensor assembly having a sensor tip which is mounted on an air bearing assembly. The air bearing assembly is suspended from a housing by a pair of bellows. In use, air is supplied to the air bearing assembly through the bellows causing the bellows to expand, lowering the sensor tip until the air bearing action stops the expansion. In another implementation of the invention, a light beam is not employed and the doping concentration profile is determined using the total capacitance, the capacitance of air, the DC bias voltage and the area of the electrode spaced from the specimen information.read more
Citations
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Patent
Methods and systems for determining a critical dimension and overlay of a specimen
Ady Levy,Kyle A. Brown,Rodney Smedt,Gary Bultman,Mehrdad Nikoonahad,Dan Wack,John Fielden,Ibrahim Abdulhalim +7 more
Patent
Real-time in-line testing of semiconductor wafers
E. Kamieniecki,Jerzy Ruzyllo +1 more
TL;DR: In this article, an apparatus and method for real-time, in-line testing of semiconductor wafers during the manufacturing process is presented, where a probe assembly is used to measure the surface photovoltage induced by the modulated light.
References
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Patent
Contactless technique for semicondutor wafer testing
TL;DR: In this article, a contactless technique for semiconductor wafer testing comprising of depositing charges on the top surface of an insulator layer over the wafer to create an inverted surface with a depletion region and thereby a field-induced junction there below in the waf, with an accumulated guard ring on the semiconductor surface there around.
Patent
Apparatus for making surface photovoltage measurements of a semiconductor
TL;DR: In this article, an apparatus for making ac surface photovoltage (SPV) measurements of a specimen of semiconductor material under dc bias voltage conditions includes a light source whose output beam is intensity modulated, an adjustable DC bias voltage source, a conductive base for supporting the specimen and a novel capacitance type reference electrode assembly.
Patent
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Patent
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Patent
Semiconductor device having a reduced surface field strength
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