Silicon-based visible and near-infrared optoelectric devices

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.

1 - 21 . (canceled) 
     
     
         22 . A semiconductor device, comprising
 a semiconductor substrate having a disordered surface layer adjacent to a bulk silicon portion, wherein said disordered surface layer is formed via the application of a plurality of short radiation pulses to a surface of said bulk silicon portion, and wherein said disordered surface layer exhibits a reduced charge carrier mobility relative to the bulk silicon portion and a resistivity greater than about 1 ohm-m.   
     
     
         23 . The device of  claim 22 , wherein the resistivity of the disordered surface layer is in a range from about 1 ohm-m to about 10 ohm-m. 
     
     
         24 . The device of  claim 22 , wherein the surface of the bulk silicon portion is exposed to a substance during the application of the plurality of short radiation pulses so as to contain one or more inclusions. 
     
     
         25 . The device of  claim 24 , wherein a level of the one or more inclusions in the disordered surface layer in a range of about 10 11  to about 10 18 . 
     
     
         26 . The device of  claim 24 , wherein the disordered surface layer exhibits an inclusion concentration in a range of about 0.1 atom percent to about 5 atom percent. 
     
     
         27 . The device of  claim 26 , wherein the disordered surface layer exhibits an inclusion concentration in a range of about 0.1 atom percent to about 1 atom percent. 
     
     
         28 . The device of  claim 22 , wherein the short radiation pulses comprise laser pulses having a pulsewidth in a range of about 100 femtoseconds to about 30 nanoseconds. 
     
     
         29 . The device of  claim 22 , wherein the short radiation pulses comprise laser pulses having a pulsewidth in a range of about 50 femtoseconds to about 50 picoseconds. 
     
     
         30 . The device of  claim 22 , wherein the short radiation pulses have a fluence in a range of about 1 kJ/m 2  to about 12 kJ/m 2 . 
     
     
         31 . The device of  claim 22 , wherein the short radiation pulses have a central wavelength in a range of about 200 nm to about 1200 nm. 
     
     
         32 . The device of  claim 22 , wherein the short radiation pulses are applied to the semiconductor substrate at a repetition rate in a range of about 1 kHz to about 1 MHz. 
     
     
         33 . The device of  claim 22 , wherein the disordered surface layer is disposed between the bulk silicon and a metal circuitry layer. 
     
     
         34 . The device of  claim 22 , wherein the disordered surface layer exhibits a plurality of microstructures. 
     
     
         35 . The device of  claim 22 , wherein the disordered surface layer has a thickness in a range of about 10 nm to about 1 micron. 
     
     
         36 . The device of  claim 22 , wherein the bulk silicon portion comprises crystalline silicon and the disordered surface layer comprises nanocrystalline grains separated by amorphous silicon. 
     
     
         37 . The device of  claim 22 , wherein a junction formed between the bulk silicon and the disordered surface layer comprises a resistive junction. 
     
     
         38 . The device of  claim 22 , wherein a junction formed between the bulk silicon and the disordered surface layer comprises a diodic junction. 
     
     
         39 . A method of manufacturing a semiconductor device, comprising:
 irradiating a surface of a silicon substrate with a plurality of short radiation pulses so as to form a disordered surface layer thereon, wherein said disordered surface layer exhibits a reduced mobility relative to a bulk silicon portion of the silicon substrate and a resistivity greater than about 1 ohm-m.   
     
     
         40 . The method of  claim 39 , wherein the resistivity of the disordered surface layer is in a range from about 1 ohm-m to about 10 ohm-m. 
     
     
         41 . The method of  claim 39 , wherein the surface of the silicon substrate is exposed to a substance while irradiating so as to contain one or more inclusions provided by the substance.