Fabrication and modeling of gigahertz photodetectors in heteroepitaxial Ge-on-Si using a graded buffer layer deposited by low energy plasma enhanced CVD

Photodetectors were fabricated in a heteroepitaxial Ge-on-Si deposited by low energy plasma enhanced CVD. Dark current density of 4.6 nA//spl mu/m, 49 % quantum efficiency, and a -3 dB bandwidth of 3.5 GHz were measured at 1.3 /spl mu/m wavelength and -3 V bias. Numerical simulations predict device modifications can achieve 10 Gbps (/spl cong/ 7 GHz) bandwidth.