Use of nitrogen as a carrier gas in LP-MOCVD for growth of GaAs AlGaAs and quantum well infrared photodetectors heterostructures

Abstract

In this paper the growth of GaAs and AlGaAs metal organic chemical vapor deposition (MOCVD) when nitrogen is used as carrier gas instead of hydrogen have been investigated. Properties of epilayers were studied in dependence from such parameters of epitaxy process as V/III ratio in gas phase, susceptor temperature and pressure in reactor. We fixed a conductivity types conversion from n- to p-type when mole fraction of Al in AlGaAs was increased from 19% to 67%. The abroad of conversion is near 40%. The increasing of methyl-radicals from trimethylaluminum concentration is a possible reason of this fact. To demonstrate the possibility of device structure growth by using in MOCVD nitrogen as carrier gas in first time the Quantum Well Infrared Photodetectors heterostructures have been fabricated. Some features of devices parameters are discussed. A device with mesa-structure has a dark current density of 1(DOT)10 -6 A at U equals 2 V and T equals 77 K; the responsivity at U equals 2 V and 45 degree(s) angle incidence of IR-radiation was S equals 0.1 A/W ((lambda) max equals 10.7 mkm).