ALGASB/GASB DIODES GROWN BY MOLECULAR-BEAM EPITAXY

AlGaSb p-i-n diodes have been grown by molecular-beam epitaxy on (100) and (111) B substrates, with the devices grown on (111) B substrates exhibiting a higher breakdown voltage and lower leakage current than those grown on (100) substrates. The superior performance of devices fabricated on (111) substrates is attributed to the improved incorporation of Sb during growth on the Sb-rich (111) B face. Increasing the Sb incorporation reduces the density of p-type native defects and thus improves intrinsic layer quality. It is also shown that the best surface morphology is obtained by utilizing slightly misoriented (111) B substrates.