SULFIDE PASSIVATION OF GASB GAINASSB/GAALASSB PHOTODIODE HETEROSTRUCTURES/

Gallium antimonide and its solid solutions are widely used to create o ptoelectronic devices for the spectral range 2-5 mu m. However, the hi gh chemical activity of their surfaces leads to a high growth rate of the native oxide and to degradation of the characteristics of devices based on these materials. The passivation of GaSb and the quaternary c ompounds GaInAsSb and GaAlAsSb based on it in aqueous solutions of Na2 S and (NH4)(2)S is investigated. It was found that an etching phase is present when such semiconductor materials are treated in aqueous sulf ide solutions. The effect of the treatment process (the type and molar ity of the solution and the treatment time) on the etch rate of the te st materials was investigated. The optimum technological conditions fo r passivating GaSb/GaInAsSb/GaAlAsSb mesa photodiode structures are de termined on the basis of the results obtained, and a significant decre ase (5-10 fold)in the value of the reverse dark current is obtained. ( C) 1997 American Institute of Physics.