Patent ID: 7239392

Claim:
A method of determining physical characteristics of a semiconductor electronic interface, the method comprising the steps of: a) illuminating an area of a surface of a semiconductor material wherein the semiconductor material comprises one or more electronic interfaces with a wavelength tunable laser source having a center wavelength nearby to at least one critical point in the optical response of the semiconductor material, with a wavelength tuning range of approximately 15 nm or greater, and using a focal spot size of 50 microns or less, wherein the laser beam is split into separate pump and probe arms, the pump arm is passed through a phase modulator followed by a polarizer to achieve amplitude modulation of the pump beam, and the pump and probe beams are spatially overlapped prior to illuminating the semiconductor material; b) recording the reflected alternating current light from the illumination of the semiconductor material, wherein the alternating current light contains one of the photo-induced changes in the semiconductor optical response, known as the photoreflectance signal, and the difference in the linear reflectivity of the “p” and “s” components of polarization, known as the linear reflectance signal, or both; c) repeating steps a) and b) across the tuning range of the laser source of step a) so as to collect wavelength information in the vicinity of critical points in the optical response of the semiconductor material; d) repeating steps a) and b) across the power range of the laser source so as to collect intensity information in the vicinity of critical points in the optical response of the semiconductor material; and e) generating an output in visual or electronic format using the information collected in steps c) and/or d), wherein the output is indicative of one or more physical characteristics of the semiconductor material.