Abstract: A method of z-scan photo-reflectance characterization of semiconductor structures and apparatus for same has been developed. The method and apparatus provides the ability to independently measure electro-refractive and electro-absorptive nonlinearities that occur in conventional photo-reflectance signals. By performing a series of photo-reflectance measurements, each containing photo-modulated nonlinear optical signals, with the sample at a multiplicity of positions along the focal length of the probe light column, and with an aperture fixtured in the reflected probe path, precision characterization of both electro-refractive and electro-absorptive nonlinearities is attained. The Z-scan photo-reflectance method and apparatus characterizes spatial distortions of a coherent photo-reflectance probe light beam due to electro-refractive and electro-absorptive effects.

Abstract: A new method of photo-reflectance characterization of strain and active dopant in semiconductor structures has been developed for characterization of physical properties of semiconductor structures. The underlying principle of the strain and active dopant characterization technique is to measure photo-reflectance signals occurring nearby to interband transitions in the semiconductor bandstructure and which are highly sensitive to strain and/or active dopant through the effect of the nanometer scale space charge fields induced at the semiconductor surface. To attain this, the present disclosure comprises an intensity modulated pump laser beam and a continuous wave probe laser beam, focused coincident on a semiconductor structure. The pump laser provides approximately 15 mW optical power in the NIR-VIS. The pump light is amplitude modulated by a signal generator operating in the range of 100 kHz-50 MHz.

Abstract: A polarization modulation photoreflectance technique has been developed for optical characterization of semiconductor electronic interfaces. By using a laser source in conjunction with polarization state modulation, a polarization modulation spectroscopy technique may be used to characterize the optical response of semiconductor materials and structures. Disclosed methods and instruments are suitable for characterization of optical signatures of electronic interfaces, including characterization of electric fields at semiconductor interfaces.