Reactive sputtering of Si/SiNx quarter-wave dielectric mirrors using in-situ laser reflectometry

We demonstrate a computer automated system for reactive sputter deposition of silicon and silicon nitride that features a laser reflectometer as an in-situ monitoring tool. A hollow anode was designed specifically for this purpose and enables in-situ reflectivity measurements at normal incidence to the wafer. We describe the use of this system for in-situ determination of the deposition rate and the material optical properties (refraedve index and loss). Finally we describe the fabrication of high precision Si/SiNx quarter-wave dielectric mirrors for opto-electronic applications by means of an in-situ feedback control algorithm.