title: Frequency response and bandwidth enhancement in Ge/Si avalanche photodiodes with over 840 GHz gain-bandwidth-product.
abstract: In this work we report a separate-absorption-charge-multiplication Ge/Si avalanche photodiode with an enhanced gain-bandwidth-product of 845 GHz at a wavelength of 1310 nm. The corresponding gain value is 65 and the electrical bandwidth is 13 GHz at an optical input power of -30 dBm. The unconventional high gain-bandwidth-product is investigated using device physical simulation and optical pulse response measurement. The analysis of the electric field distribution, electron and hole concentration and drift velocities in the device shows that the enhanced gain-bandwidth-product at high bias voltages is due to a decrease of the transit time and avalanche build-up time limitation at high fields.
authors: University of California Santa Barbara, ECE Department, Santa Barbara, CA 93106, USA. wissem@ece.ucsb.edu
authors: Wissem Sfar
authors: WS
authors: Zaoui
authors: Hui-Wen
authors: HW
authors: Chen
authors: John E
authors: JE
authors: Bowers
authors: Yimin
authors: Y
authors: Kang
authors: Mike
authors: M
authors: Morse
authors: Mario J
authors: MJ
authors: Paniccia
authors: Alexandre
authors: A
authors: Pauchard
authors: Joe C
authors: JC
authors: Campbell
mesh_terms: D000465:Algorithms; D001709:Biotechnology / Q000379:methods; D003198:Computer Simulation; D004581:Electronics; D004867:Equipment Design; D005857:Germanium / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D015233:Models, Statistical; D055095:Optics and Photonics; D011789:Quantum Theory; D012825:Silicon / Q000737:chemistry*
chemical_list: D005857:Germanium; D012825:Silicon