Recrystallization method to selenization of thin-film Cu(In,Ga)Se.sub.2 for semiconductor device applications

US5436204A · kind A · utility

Assignee

• Midwest Research Institute, Inc. · US

Inventors

• David S. Albin · Denver, US
• Jeffrey J. Carapella · Evergreen, US
• John R. Tuttle · Boulder, US
• Miguel A. Contreras · Golden, US
• Andrew Gabor · Boulder, US
• Rommel Noufi · Golden, US
• Andrew L. Tennant · Denver, US

Key dates

• Filing date: Aug 22, 1994
• Grant date: Jul 25, 1995
• Expiry date: Aug 22, 2014

Classification

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

Abstract

A process for fabricating slightly Cu-poor thin-films of Cu(In,Ga)Se.sub.2 on a substrate for semiconductor device applications includes the steps of forming initially a slightly Cu-rich, phase separated, mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se on the substrate in solid form followed by exposure of the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture to an overpressure of Se vapor and (In,Ga) vapor for deposition on the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture while simultaneously increasing the temperature of the solid mixture toward a recrystallization temperature (about 550.degree. C.) at which Cu(In,Ga)Se.sub.2 is solid and Cu.sub.x Se is liquid. The (In,Ga) flux is terminated while the Se overpressure flux and the recrystallization temperature are maintained to recrystallize the Cu.sub.x Se with the (In, Ga) that was deposited during the temperature transition and with the Se vapor to form the thin-film of slightly Cu-poor Cu.sub.x (In,Ga).sub.y Se.sub.z. The initial Cu-rich, phase separated large grain mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se can be made by sequentially depositing or co-depositing the metal precursors, Cu and (In, Ga), on the substrate at room temperature,…