Diode structures from amorphous low-temperature GaAs

Effect of annealing on electrical properties of GaAs diode structure that incorporates a nominally undoped LT layer on top of conventionally grown p-type GaAs is examined. Unannealed GaAs grown by MBE at substrate temps. < 250 degrees C is amorphous and highly resistive. Annealing at high temps. converts undoped LT GaAs from amorphous to single-crystal material. Annealed material is n-type. c-v characteristics of LT on p-type GaAs structures shows greater symmetry, with lower reverse leakage currents, as anneal temp. is increased to > 400 degrees . This reflects improved crystal quality of the LT layer.