Patent ID: 6197606
Filing Date: 2001-03-06
Classification: H01L

Abstract:
A nondestructive method for estimating a thickness of a denuded superficial layer with respect to a relatively defective bulk region of a monocrystalline semiconductor wafer, the method comprising the steps of:stripping off the denuded superficial layer from at least a first portion of the wafer;separately measuring a minority carrier lifetime in the first portion of the wafer, and a surface photovoltage signal as a function of a light penetration depth in a second portion of the wafer having the denuded layer thereon, while injecting minority charge carriers at a low level for a depth sufficient to encompass both the denuded superficial layer and at least a portion of the bulk region; andcalculating the thickness of the denuded layer as the depth required to account for the measured minority carrier lifetime and for the measured surface photovoltage signal versus the light penetration depth.