Non-destructive thickness measurements of GaInAs, AlInAs, and InP multilayer structures

Thickness measurements of various three and four layer structures on InP substrates using the non-destructive technique of spectroscopic ellipsometry are discussed. The individual layer thicknesses ranged from 150 Å to 4500 Å, and excellent agreement was found between the values obtained from the ellipsometric model and the values obtained on the same samples from conventional destructive thickness measurements (TEM and selective etching). The sensitivity of the spectroscopic ellipsometry modeling procedure to changes in thickness of the various layers is demonstrated and compared to X-ray diffraction modeling of the same layers