PHOTOREFLECTANCE INVESTIGATIONS OF SEMICONDUCTOR-DEVICE STRUCTURES

The application of photoreflectance (PR) spectroscopy to metal-semicon ductor field effect transistor and high electron mobility transistor s tructures is demonstrated. The line shape analysis relies on a new met hod for calculating PR spectra and electric field profiles of heterost ructures with weakly inhomogeneous layers. The method allows inhomogen eous built-in electric field distributions below the surface to be det ected. It can be used to determine characteristic parameters of device structures and to detect quantum states confined to potential wells. Differences between PR spectra from nominally identical or similar str uctures are attributed to different interface qualities.