Enhanced quality thin film Cu(In,Ga)Se2 for semiconductor device applications by vapor-phase recrystallization

Abstract

Abstract Enhanced quality thin films of Cu w (In,Ga y )Se z for semiconductor device applications are fabricated by initially forming a Cu-rich, phase-separated compound mixture comprising Cu(In,Ga):Cu x Se on a substrate to form a large-grain precursor and then converting the excess Cu x Se to Cu(In,Ga)Se 2 by exposing it to an activity of In and/or Ga, either in vapor In and/or Ga form or in solid (In,Ga) y Se z . Alternatively, the conversion can be made by sequential deposition of In and/or Ga and Se onto the phase-separated precursor. The conversion process is preferably performed in the temperature range of about 300°-600° C., where the Cu(In,Ga)Se 2 remains solid, while the excess Cu x Se is in a liquid flux. The characteristic of the resulting Cu w (In,Ga) y Se z can be controlled by the temperature. Higher temperatures, such as 500°-600° C., result in a nearly stoichiometric Cu(In,Ga)Se 2 , whereas lower temperatures, such as 300°-400° C., result in a more Cu-poor compound, such as the Cu z (In,Ga) 4 Se 7 phase.

Inventors

• 👤 John R. Tuttle
• 👤 Miguel A. Contreras
• 👤 Rommel Noufi
• 👤 David S. Albin

Bibliographic Details