NEW SELECTIVE METALORGANIC CHEMICAL-VAPOR-DEPOSITION GROWTH METHOD FOR INALAS WITH HIGH ALUMINUM COMPOSITION

Selective growth was achieved for the pair of InAlAs and successively deposited InP when the InAlAs thickness was of the order of several nanometers even under growth conditions where thick InAlAs could not be grown selectively. The ''critical thickness'' of InAlAs for the selective growth of InP/InAlAs was found to be of a certain value in the range of 40 to 100 nm. This ''critical thickness'' was mainly determined by the total InAlAs thickness, but increased slightly with an increase of the diffusion duration of precursor adatoms of InAlAs on a SiO2 mask. Although the thickness of several nanometers was very small, it was confirmed to be sufficiently large to attain a large band gap and current blocking enhancement effect of InAlAs in the p-n junction. When a thin layer of In0.4Al0.6As was inserted into a laser diode current blocking layer, an improvement of the laser diode temperature characteristics was confirmed.