Metallic p-type GaAs and GaAlAs grown by metalorganic molecular beam epitaxy

The potential of metalorganic molecular beam epitaxy (MOMBE) for the growth of extremely low resistivity p-tape GaAs and GaAlAs has been investigated. The acceptor is carbon which is incorporated from trimethylgallium. The hole concentration was controlled in the range 10 19 -10 21 cm -3 by changing the growth temperature. The highest hole concentrations of 1.5×10 21 and 2.5×10 21 cm -3 have been obtained for GaAs and GaAlAs with the Al mole fraction of 0.35, respectively, which are higher than any other values reported for p-type epitaxial GaAs and GaAlAs thin films. The growth mechanism and detailed electrical properties have been discussed. It was found that the behavior of carbon as an acceptor is much more suitable than that of beryllium for device applications, which require thin layers with ultra low resistivity.