PERFORMANCE OF GAXIN1-XP/GAAS HETEROJUNCTIONS GROWN BY METAL-ORGANIC MOLECULAR-BEAM EPITAXY AND METAL-ORGANIC VAPOR-PHASE EPITAXY

The electrical and structural characteristics of GaIn1-xP/GaAs heterostructures grown by metal-organic molecular-beam epitaxy (MOMBE) at 480-560-degrees-C and metal-organic vapor-phase epitaxy (MOVPE) at 700-degrees-C are comparatively studied. For the lattice-matched composition (x=0.51) transport in Schottky diodes fabricated on MOVPE material is almost thermionic and the barrier height is 0.96+/-0.05 eV. Deviation from the ideal thermionic behavior is observed in diodes on MOMBE material and the deviation is stronger as the growth temperature decreases. The undoped MOMBE material, grown at T(G) less-than-or-equal-to 520-degrees-C, as well as the MOVPE material, are characterized by a deep electron trap with an activation energy of 0.80+/-0.05 meV. The formation of this trap in the MOMBE and MOVPE material is suppressed by doping with shallow impurities, at doping levels higher than 10(17) cm-3. However, doping of MOMBE Ga0.51In0.49P (hereafter called GaInP) with S and Si introduces another trap with an activation energy of about 300 meV, which has some of the properties of the DX centers, while Se doping of MOVPE GaInP does not introduce any donor-related traps. Rapid thermal annealing of the MOMBE material, at temperatures up to 600-degrees-C, improves the Schottky barrier characteristics and reduces the deep trap concentration. An additional trap with an activation energy of about 500 meV, that has been identified in lattice-matched MOMBE Ga0.51In0.49P epilayers, is attributed to the electrical activity of dislocations, which have been identified with transmission electron microscopy (TEM) studies. Furthermore, the TEM analysis reveals the presence of compositional separation phenomena (spinodal decomposition) which are strong in the MOMBE material and less extended in the MOVPE material.