Intermetallic Semiconductor Buffered Substrate
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
The buffered substrate structure is shown in the figure. It consists of a low dislocation substrate such as an In-doped substrate, a superlattice structure consisting of 5 or more layer combinations of GaAlAs, with 50% or more Al, and GaAs layers of 100-500 Angstroms each, and a GaAs final layer doped with a deep acceptor, such as Cr, Fe, V, or Ni, with a concentration of 5 x 1014 & Na & 5 x 1015, and a thickness of 1 to 5 microns. The deep acceptor acts as both a compensator to provide semi-insulating properties and a trap to raise the trap-filled limit voltage and prevent space-charge-limited currents which contribute to back and side-gating. Both molecular beam epitaxy metal organic chemical vapor deposition can be used to obtain the epitaxial layers.