Silicon-based visible and near-infrared optoelectric devices

Patent metadata

Field	Value
Publication number	US-9276143-B2
Application number	US-201314100954-A
Country	US
Kind code	B2
Filing date	Dec 9, 2013
Priority date	May 25, 2001
Publication date	Mar 1, 2016
Grant date	Mar 1, 2016

Abstract

In one aspect, the present invention provides a silicon photodetector having a surface layer that is doped with sulfur inclusions with an average concentration in a range of about 0.5 atom percent to about 1.5 atom percent. The surface layer forms a diode junction with an underlying portion of the substrate. A plurality of electrical contacts allow application of a reverse bias voltage to the junction in order to facilitate generation of an electrical signal, e.g., a photocurrent, in response to irradiation of the surface layer. The photodetector exhibits a responsivity greater than about 1 A/W for incident wavelengths in a range of about 250 nm to about 1050 nm, and a responsivity greater than about 0.1 A/W for longer wavelengths, e.g., up to about 3.5 microns.

First claim

What is claimed is:

1. A method of processing a semiconductor substrate, comprising
depositing a solid charge-donating substance on a surface of a semiconductor substrate,
subsequently, irradiating said surface with a plurality of laser pulses having a pulse width in a range of about 50 femtoseconds to about 50 picoseconds incorporating at least a portion of said solid charge-donating substance into a surface layer of said semiconductor substrate at a concentration in a range of about 0.5 to about 5 atom percent,
wherein a diode junction is formed with an underlying portion of the substrate.

2. The method of claim 1 , wherein the solid charge-donating substance is a solid electron-donating substance.

3. The method of claim 2 , wherein said solid electron-donating substance comprises any of selenium and tellurium.

4. The method of claim 1 , wherein said pulse width is in a range of about 50 femtoseconds to about 500 femtoseconds.

5. The method of claim 1 , wherein said semiconductor substrate has an electrical resistivity in a range of about 0.001 ohm-m to about 10 ohm-m prior to said step of irradiating.

6. The method of claim 1 , wherein said pulses have fluence in a range of about 1 kJ/m 2 to about 12 kJ/m 2 .

7. The method of claim 1 , wherein said pulses have a central wavelength in range of about 200 nm to about 1200 nm.

8. The method of claim 1 , wherein said semiconductor substrate is a silicon substrate.

9. The method of claim 1 , wherein said pulses are applied to the semiconductor substrate at a repetition rate in a range of about 1 kHz to about 1 MHz.

Assignees

• Harvard College

Inventors

• Mazur Eric
• Carey James Edward

Classifications

• H10P14/3816

  Pulsed laser beam · CPC title

• H10P14/3411

  Silicon, silicon germanium or germanium · CPC title

• H10P34/42

  with electromagnetic radiation, e.g. laser annealing (laser cutting H10P54/20) · CPC title

• Y02E10/547

  Monocrystalline silicon PV cells · CPC title

• Y02E10/52

  PV systems with concentrators · CPC title