Ultimate Silicon^TM is Siltronic’s highly specialized wafer for leading-edge CMOS applications such as DRAM devices. Ultimate Silicon^TM wafers have smaller sized defect levels (LPDs) than standard polished prime wafers. In part, due to lack of nucleation sites for oxygen precipitates the gettering capability is limited. The Ultimate Silicon^TM crystal process meets stringent oxygen concentration and radial distribution requirements. Other wafer parameters like flatness, flat- and backside roughness are comparable to standard wafers. Siltronic offers Ultimate Silicon^TM wafers with diameter of 300 mm only.