Porous silicon photo-device capable of photoelectric conversion

• US 5,644,156 A
• Filed: 04/12/1995
• Issued: 07/01/1997
• Est. Priority Date: 04/14/1994
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Zhang, Li, Sakai, Tadashi, Suzuki, Taketoshi, Murakami, Taijun
• Primary Examiner(s): Ngo , Ngan V.
• Application Number:
  US08/420,515
• Time in Patent Office: 811 Days
• Field of Search: 257/3, 257/309, 257/485, 257/618, 257/647
• US Class Current: 257/485
• CPC Class Codes: H01L 29/16 including, apart from doping materials or other impurities, only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 29/47 Schottky barrier electrodes H01L29/435 takes precedence
• CPC Class Codes: H01L 31/0284 comprising porous silicon as part of the active layer(s) porous silicon as antireflective layer for photodiodes H01L31/0216; for solar cells H01L31/02168
• CPC Class Codes: H01L 31/173 formed in, or on, a common substrate
• CPC Class Codes: H01L 31/1804 comprising only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 33/346 containing porous silicon
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A semiconductor device includes a porous silicon layer with an impurity concentration of 1×10¹⁹ to 1×10²¹ cm^-3, in which a plurality of pores are formed, and a thermal oxide film 0.01 to 10 μm thick formed on the expanded surfaces of the porous silicon layer, wherein said expanded surfaces include internal surface of said pores.

Claims

1. A semiconductor device comprising:

a porous silicon layer made from single crystalline silicon as a base with an impurity concentration of 1×

10¹⁹ to 1×

10²¹ cm^-3, in which a plurality of pores are formed; and

a thermal oxide film of 0.01 to 10 μ

m thickness, formed on expanded surfaces of said porous silicon layer, said expanded surfaces including internal surfaces of said pores.

2. A semiconductor device comprising:

a silicon substrate having a major surface;

a first porous silicon layer of a first conductivity type with an impurity concentration of 1×

10¹⁹ to 1×

10²¹ cm^-3, which is formed on the major surface of said silicon substrate, and in which a plurality of pores are formed;

a second porous silicon layer of a second conductivity type with an impurity concentration of 1×

10¹⁹ to 1×

10²¹ cm^-3, in which a plurality of pores are formed and which are formed on said first silicon layer to form a p-n junction with said first silicon layer; and

a thermal oxide film 0.01 to 10 μ

m thick formed on expanded surfaces of said first and said second porous silicon layers said expanded surfaces including internal surfaces of said pores; and

an electrode selectively formed on said second porous silicon layer of the second conductivity type.

3. A device according to claim 2, wherein said electrode is essentially a transparent electrode, and said p-n junction has a luminescent function.

4. A device according to claim 2, wherein said second silicon layer of the second conductivity type are formed by making the major surface of said substrate of the first conductivity type porous, and by doping an impurity of the second conductivity type into upper portions of said second silicon layer, the remaining portions of said first silicon layer of the first conductivity type forming said p-n junction with said second silicon layer of the second conductivity type.

5. A semiconductor device comprising:

a substrate having a major surface;

a porous silicon layer with an impurity concentration of 1×

10¹⁹ to 1×

10²¹ cm^-3, which is formed on the major surface of said silicon substrate, and in which a plurality of pores are formed;

a thermal oxide film 0.01 to 10 μ

m thick formed on expanded surfaces of said porous silicon layer, said expanded surfaces including internal surfaces of said pores; and

an electrode selectively formed on said porous silicon layer, in order to form an ohmic junction with said porous silicon layer.

6. A device according to claim 5, wherein said electrode is essentially a transparent electrode, and said ohmic junction has a luminescent function.

7. A device according to claim 6, wherein said electrode is a transparent electrode consisting of an ITO (Indium Tin Oxide) film.

8. A semiconductor device comprising:

a substrate having a major surface;

a porous silicon layer with an impurity concentration of 1×

10¹⁹ to 1×

10²¹ cm^-3, which is formed on the major surface of said silicon substrate, and in which a plurality of pores are formed;

a thermal oxide film 0.01 to 10 μ

m thick formed on expanded surfaces of said porous silicon layer said expanded surfaces including internal surfaces of said pores; and

an electrode selectively formed on said porous silicon layer, in order to form a Schottky junction with said porous silicon layer.

9. A device according to claim 8, wherein said electrode is essentially a transparent electrode, and said Schottky junction has a luminescent function.