Previously developed methods used to grow Ge1- ySny alloys on Si are extended to Sn concentrations in the 1019-1020cm-3 range. These concentrations are shown to be sufficient to engineer large increases in the responsivity of detectors operating at 1550 nm. The dopant levels of Sn are incorporated at temperatures in the 370-390 C range, yielding atomically smooth layers devoid of threading defects at high growth rates of 15-30 nm/min. These conditions are far more compatible with complementary metal-oxide semiconductor processing than the high growth and processing temperatures required to achieve the same responsivity via tensile strain in pure Ge on Si. A detailed study of a detector based on a Sn-doped Ge layer with 0.25 (1.1 1020cm-3) Sn range demonstrates the responsivity enhancement and shows much better I-V characteristics than previously fabricated detectors based on Ge 1-ySny alloys with y 0.02.
ASJC Scopus subject areas
- Physics and Astronomy(all)