III-V solar cells and doping processes

US5217539A · kind A · utility

Assignee

• The Boeing Company · US

Inventors

• Lewis M. Fraas · Malibu, US
• Veeravana S. Sundaram · Issaquah, US
• James E. Avery · Issaquah, US
• Peter E. Gruenhaum · Seattle, US
• Eric Malocsay · Bellevue, US

Key dates

• Filing date: Sep 5, 1991
• Grant date: Jun 8, 1993
• Expiry date: Sep 5, 2011

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P70/50

Abstract

Zinc diffusion procedures applicable for large scale manufacture of GaAs and GaSb cells used in tandem solar cells having a high energy conversion efficiency. The zinc doping and carrier concentration are restricted to be less than about 10.sup.19 /cm.sup.3 to obtain good light generated carrier collection and hence good short circuit currents. The amount of zinc that is available for diffusion during a drive-in heating step is restricted. Confinement of zinc and arsenic vapors during the heating step may be effected by use of a proximity source wafer or by an encapsulant layer. The zinc diffusion of GaSb is obtained by a homogeneous light diffusion that is followed by a patterned heavy diffusion to give low ohmic contact with the grid lines. Texture etching of the GaSb solar cell is also compatible with this diffusion process.