A new fringe method for characterization of ROUGHNESS of inner layrs in semiconductor crystals and dielectric thin layrs

点击翻译按钮获取中文摘要

A new fringe method was developed for characterization of "roughness" of inner layrs and interfaces in semiconductor devices because the roughness are very important for semiconductor technologies. Here, brightness and clearness, or visibility, of the fringe pattern are determined by scattering from the objects to be surveyed, because size and density of dots and spots which compose the fringes are proportional to size and density of particles and grains located at the interfaces or roughness on the layrs while their scattered intensities are dependent upon refractive index difference between matrix and the objects.(1) A SIMOX wafer is prepared by proper heat treatments from a silicon wafer showered by heavy but homogeneous implantation of oxygen ions, and thus a thin and flat oxide layr is generated in the wafer. The layr is made of fine oxide particles which efficiently act as light scatterers. The fringe patterns obtained by SIMOX wafers are usually bright and clear with fine dots w … More hich inform us the layr is a homogeneous assemble of fine oxide particles.(2) when denuded zone and oxide particles for intrinsic gettering (IG) are generated in a CZ-Si wafer after application of proper heat treatments to the wafer, an interface between the zone and the IG region is clearly observed by this fringe method. Oxide particles located near the interface are quantitatively measured, which is very important for planar circuits on the wafer.(3) Optical quality of multi-layrs with quantum well structure was comprehensively checked by this fringe method because this fringe pattern will be observed only when any optical inhomogeneity is present in the layrs grown on substrate.(4) Since etch pits and steps on crystal faces indicate crystallographic anisotropy, the light intensities scattered by the pits and steps are dependent upon the direction of incident light against their crystallographic orientations, which has been clearly observed by some GaAs wafers.To measure "roughness" of inner layrs or interfaces which are unable to measure before this fringe method, a new method has been developed here, which is, of course, governed by an electronic system. Less