Control of a reactive ion etching process for InP and related materials by in-situ ellipsometry in the near infrared

The use of in-situ ellipsometry at a wavelength of 1300 nm for etch depth measurement and endpoint detection during reactive ion etching (RIE) of InGaAs(P)/InP heterostructures is reported. The basic principle and the experimental technique are briefly described. It is shown that etch depth monitoring and endpoint detection can be performed as low as 0.1. Furthermore, the method has been used for in-situ measurement of the wafer temperature during plasma exposure.<>