EFFECT OF PHOSPHORUS ON ELECTRICAL-PROPERTIES OF UNDOPED INP GROWN ATLOW-TEMPERATURE BY ATOMIC LAYER MOLECULAR-BEAM EPITAXY

Undoped InP layers grown at low temperature by atomic layer molecular beam epitaxy have been studied by Hall measurements and deep level tra nsient spectroscopy. The fee carrier concentration at room temperature increases linearly with phosphorus pressure and it has been possible to obtain layers with a free carrier concentration of 1 x 10(16) cm(-3 ) and an electron mobility of about 3000 cm(2) V-1 s(-1), which are si milar to values for samples grown at high temperatures. Deep level tra nsient spectroscopy shows the presence, in all the samples, of five el ectron traps with emission energies of 0.60, 0.40, 0.25, 0.16, and 0.1 1 eV from the conduction band, with concentrations independent of the free carrier concentration with the exception of the 0.40 eV trap conc entration, which increases slightly with free carrier concentration. ( C) 1996 The Institute of Materials.