We report a metal-Ge-metal photodetector fabricated on a Ge epitaxial layer grown on Si (100) substrate. Amorphous Ge was used to increase the Schottky barrier height, which resulted in a reduction of the dark current by more than two orders of magnitude. The dark current measured on a photodetector having 1 μm finger width and 2 μm spacing with 25 × 50 μm 2 active area was 7.5 μA at 3 V. At the wavelength of 1.3 μm, the external quantum efficiency was 14.3% (0.15 A/W) without an antireflecting coating. At reverse biases of 1, 2, 3, and 4 V, the 3-dB bandwidth was found to be 1.5,2.8,3.1, and 4.3 GHz, respectively.
Bibliographical noteFunding Information:
Manuscript received August 6, 2003; revised September 7, 2003. This work was supported by the Motorola SABA program and by DARPA CHIPS Center. The authors are with the The University of Texas at Austin, Austin, TX 78712 USA (e-mail: email@example.com). Digital Object Identifier 10.1109/LPT.2003.822258
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering