Solar cell

• US 4,900,369 A
• Filed: 12/14/1988
• Issued: 02/13/1990
• Est. Priority Date: 10/11/1985
• Status: Expired due to Fees

• Current Assignee: NUKEM GmbH (Cameco Corporation)
• Original Assignee: NUKEM GmbH (Cameco Corporation)
• Inventors: Hackstein, Karl G., Hezel, Rudolf
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US07/284,420
• Time in Patent Office: 426 Days
• Field of Search: 136/255, 136/256
• US Class Current: 136/255
• CPC Class Codes: H01L 31/02167 for solar cells
• CPC Class Codes: H01L 31/022425 for solar cells
• CPC Class Codes: H01L 31/062 the potential barriers being only of the metal-insulator-semiconductor type
• CPC Class Codes: H01L 31/068 the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells

Abstract

A solar cell (10) is proposed, particularly of silicon, having a semiconductive substrate (1) on one side of which an electrical field is provided by, for example, an MIS contact (1, 2, 3) to cause a separation of charge carriers generated by light energy. The minority charge carriers are drawn into the metal (3) of the MIS contact, whereas the majority charge carriers are discharged via ohmic contact zones (4) arranged on the opposite side of the semiconductive substrate. At least one passivation layer (5) is arranged on the semiconductive substrate between the ohmic contact zones, whereby the recombination velocity of the charge carriers in the area of the ohmic contact zones is considerably reduced.

Claims

1. A solar cell comprising:

a substrate layer of semiconductor material of a first conductivity type, in which energy from a radiation source generates minority and majority charge carriers, the substrate layer having a first surface facing the front of the cell and a second surface facing the rear of said cell;

a highly doped semiconductor layer of second conductivity type formed on said first surface of said substrate layer, said second conductivity type being opposite to said first conductively type;

a plurality of spaced first ohmic contacts formed on said highly doped layer;

a plurality of spaced second ohmic contacts formed directly on said second surface of said substrate layer,

an insulation, passivation, and antireflection layer formed over and between said second ohmic contacts,

said highly doped semiconductor layer of second conductivity type forming junction means for providing an electrical field for separating the minority and majority charge carriers in the region of the first surface of said substrate layer so that the majority charge carriers diffuse to said second ohmic contacts and are collected by them, the thickness of said substrate layer being less than or equal to the diffusion length of the minority charge carriers in said substrate layer.

2. A solar cell according to claim 1 further comprising a front surface anti-reflection layer formed over said first ohmic contacts.

3. A solar cell according to claim 1 wherein said first ohmic contacts are arranged in a grid form.

4. A solar cell according to claim 1 wherein said second ohmic contacts are arranged in a grid form.

5. A solar cell according to claim 1 wherein said insulation, passivation, and antireflection layer is aluminum oxide.

6. A solar cell according to claim 1 wherein said insulation, passivation and anti-reflection layer is silicon nitride.

7. A solar cell according to claim 1 wherein said highly doped layer is doped with phosphorus atoms.

8. A solar cell according to claim 1 wherein said insulation, passivation, and anti-reflection layer has a thickness of 2-300 nm.

9. A solar cell according to claim 1 wherein said cell is adapted so that the front of the cell receives radiation from said radiation source.

10. A solar cell according to claim 1 wherein said cell is adapted so that the rear of the cell receives radiation from said radiation source.

11. A solar cell according to claim 1 wherein said cell is adapted so that both the front and rear of the cell receive radiation from said radiation source.