This work presents the limiting factors of fast Germanium p-i-n photodetectors for optical on-chip communication. The photodetectors are grown by molecular beam epitaxy on Silicon and Silicon on insulator substrates. On-wafer RF and optical RF measurements up to 40 GHz are performed at a wavelength of 1.55 μm. Different de-embedding procedures are used to obtain the amplitude and phase of the device impedance and the equivalent circuit description. An analysis of the reflection coefficient compared to the equivalent circuit explains the frequency characteristic and it is used to determine background doping of the intrinsic layer and the expansion of the space charge width. The optical bandwidth is measured for different bias voltages and background doping. The RC limitation of the detectors is shown and analyzed leading to adjusted parameters for high speed detectors at zero-bas.

Date Published: 22 May 2013
PDF: 7 pages
Proc. SPIE 8767, Integrated Photonics: Materials, Devices, and Applications II, 87670D (22 May 2013); doi: 10.1117/12.2017008

Published in SPIE Proceedings Vol. 8767:
Integrated Photonics: Materials, Devices, and Applications II
Jean-Marc Fédéli; Laurent Vivien; Meint K. Smit, Editor(s)