HEAVILY-DOPED P-TYPE ALGAINP GROWN BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION

In order to obtain metalorganic chemical vapor deposition (MOCVD) grow n (AlxGa1-x)(0.5)In0.5P (x = 0.4 and 0.7) with as high as possible hol e concentrations two different approaches were investigated. First, as a reference, AlGaInP was grown with the traditional precursor combina tion trimethylindium (TMIn), trimethylgallium (TMGa), trimethylalumini um (TMAl) and di-ethylzinc (DEZn) as a dopant. This was compared with layers grown with dimethylamine-alane (DMEAAl) as aluminium precursor and tri-ethylgallium (TEGa) instead of TMGa. The electrical activity o f zinc in layers grown with DMEAAl and TEGa is found to be much higher than in layers grown with TMAl and TMGa. Oxygen was identified as the main cause of Zn-acceptor compensation. The other dopant, magnesium, was used with the conventional group III precursors (TMGa, TMIn and TM Al). With both dopants, hole concentrations above 10(18) cm(-3) for x = 0.4 and close to 10(18) cm(-3) for x = 0.7 were obtained at growth t emperatures of 640 and 720 degrees C. (C) 1998 Elsevier Science B.V. A ll rights reserved.