HIGH-RATE HIGH-DENSITY ICP ETCHING OF GERMANIUM

Inductively coupled Ar/SF6 plasma (ICP) etching p-type germanium (Ge) substrate used for a multijunction solar cell (MJ SC) was investigated at different ICP power levels and SF6 flow rates at a constant working pressure of 7 Pa. The etching rate of Ge increases linearly from 11.9 to 19.4 mu m/min and surface roughness decreases as the ICP power level increases from 400 to 650 W at SF6 flow rate of 300 scan. Also, the etching rate of Ge increases by a power law from 8.0 to 16.7 mu m/min as the SF6 flow rate increases from 50 to 300 scan at ICP power of 570 W. OES and XPS studies were carried out using NIST databases. Identifications for some calculated Ritz lines were suggested.