Quantitative Inversion of Scanning Capacitance Microprobe (SCM)
With the shrinkage of semiconductor devices to the sub-micron level, a great need exists for direct, quantitative, two dimensional dopant profile measurements on a nanometer scale. Direct measurement of 2-dimensional dopant profile provides a means for improving very large scale integrated process and electrical device simulators. They are also needed to accurately calibrate and verify models built into simulators. They give rapid feedback to improve manufacture control and decrease process development time. This invention describes a novel improvement in the process where quantitative inversion of data from the scanning capacitance microscope (SCM) is achieved by using a novel feedback system and procedure incorporated into the method.
The inversion of SCM data to dopant profile is extremely difficult by methods described previously in the literature. The novel feedback system and procedure of this invention controls the AC bias voltage applied to the tip of the SCM so that the capacitance change due to depletion of majority carriers beneath the tip of the microscope moves across the surface of the sample. This means that the peak depletion depth of majority carriers beneath the tip remains approximately constant as the tip moves from a region of high dopant density to a region of lesser density.
Stage of Development
A patent (US 5523700) has been issued from the US Patent and Trademark Office. This technology is seeking partners for development-manufacturing-sales of the working, final product. It is available for developmental research support/licensing under either exclusive or non-exclusive terms.
Yunji Huang, Clayton Williams
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