(Invited) Selective Epitaxy of Submicron Ge Wire Structures for Photodetectors and Optical Modulators in Si Photonics

Abstract

A selective-area epitaxial growth of Ge on the submicron scale is studied using chemical vapor deposition (CVD) on Si in terms of the fabrication of integrated photonic devices operating at the optical communication wavelengths of around 1.55 μm. A mesa structure of Ge on the micron scale, having a vertical pin junction, is effective for fabricating a waveguide-integrated photodetector in the optical receiver. A 3-dB cutoff frequency is obtained up to approximately 50 GHz. For a higher frequency operation, a narrower structure of submicron-wide Ge wire, having a lateral pin junction, is required. Such a wire structure is also important for the application to an electro-absorption optical intensity modulator in the optical transmitter. Structural and optical properties are investigated for a submicron-wide Ge wire on Si selectively grown by CVD.