ELECTRICAL-PROPERTIES OF INALAS INGAAS MODULATION-DOPED STRUCTURE AFTER SIN PASSIVATED ANNEALING/

The effect of thermal annealing on the InAlAs/InGaAs modulation-doped structure, passivated with a SiN film, was investigated. In contrast t o the capless sample, the passivated modulation-doped sample exhibited negligible degradation in the two-dimensional electron gas concentrat ion (N-s) after annealing at 280 degrees C, indicating that SiN is an efficient passivation material to ensure good thermal stability for th e InAlAs/InGaAs modulation-doped structure. In addition, partial recov ery in N, was found by annealing the SiN-passivated sample that had ex perienced serious Ns degradation. A series of secondary ion mass spect roscopy (SIMS) measurements and Hall effect measurements revealed that the recovery of Ns is associated with the discharge of fluorine atoms from the Si-doped n-type InAlAs layer. (C) 1997 American Institute of Physics.