Germanium on Silicon Photodetectors with Broad Spectral Range

Abstract

Vertical germanium on silicon p-i-n photodetectors were grown by molecular beam epitaxy and further processed by a quasi-planar mesa process. In this paper the influence of the -top contact layer on the optical responsivity was investigated. The -top contact was realized as highly antimony-doped silicon on a germanium heterostructure. With this additional heterostructure on top (relaxed silicon on relaxed germanium), the optical responsivity of the photodetector was broadened. The visible wavelength cutoff was shifted to , whereas the long wavelength cutoff remained at .