Browse Prior Art Database

Long Wavelength Photo-Detector on Si Chips

IP.com Disclosure Number: IPCOM000119784D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 40K

Publishing Venue

IBM

Related People

Legoues, F: AUTHOR [+4]

Abstract

Disclosed are two long wavelength photodetector structures on Si chips. The structures use high Ge (> 75%) SiGe layers. This layer reduces the bandgap of Si and lowers the threshold for absorbing 1.3 mm light.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Long Wavelength Photo-Detector on Si Chips

      Disclosed are two long wavelength photodetector structures on
Si chips.  The structures use high Ge (> 75%) SiGe layers.  This
layer reduces the bandgap of Si and lowers the threshold for
absorbing 1.3 mm light.

      One device based on photoconductor concept is shown in Figure
1.  (1) indicates strain buffer layer with Ge concentration less than
20%.  (2) Si1-xGex indicates photconductor layers with Ge > 75%.  The
SiO2 layer (3) on the top of the photoconductor is a protective layer
as well as a window.  The metal contact frame is a reflector which
can also act as a light screen to prevent light from getting to an
unwanted layer. The metal to substrate is ohmic contact.

      Figure 2 is another structure in which the channel region of
FET structure contains 75% Ge and is produced by the gate oxidation
cycle.  Photocurrent in the channel is then used as the signal
detector.

      Disclosed anonymously.