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 heteros tructures grown by metal-organic molecular-beam epitaxy (MOMBE) at 480 -560-degrees-C and metal-organic vapor-phase epitaxy (MOVPE) at 700-de grees-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 mat erial and the deviation is stronger as the growth temperature decrease s. 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 forma tion of this trap in the MOMBE and MOVPE material is suppressed by dop ing 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 30 0 meV, which has some of the properties of the DX centers, while Se do ping of MOVPE GaInP does not introduce any donor-related traps. Rapid thermal annealing of the MOMBE material, at temperatures up to 600-deg rees-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 Ga 0.51In0.49P epilayers, is attributed to the electrical activity of dis locations, which have been identified with transmission electron micro scopy (TEM) studies. Furthermore, the TEM analysis reveals the presenc e of compositional separation phenomena (spinodal decomposition) which are strong in the MOMBE material and less extended in the MOVPE mater ial.