Single-wafer Si and SiGe processes for advanced ULSI technologies

Abstract

Low thermal budget as well as new industrially processable materials will be key issues in future advanced CMOS (≤0.18 μm) and bipolar technologies. Low-temperature deposition of Si and Si 1− x Ge x (referred to as SiGe hereafter) has been performed using an industrial, 200 mm, single-wafer CVD module operating at reduced pressure. Epitaxial Si and heteroepitaxial SiGe growth has been studied for buried channel applications in CMOS devices or as a base for heterojunction bipolar transistors (HBTs), as well as polycrystalline SiGe with a high Ge content as a potential alternative material for poly-gate stacks. The dependence of the deposition rate on the filling ratio and window size, and its evolution with the addition of HCl to the gas mixture is investigated for selectively grown SiGe layers. The pattern dependence of the Ge content is also presented. Preliminary results on poly-SiGe films with Ge contents up to 100% are shown and discussed.