Electrical investigation of carbon intrinsically‐doped GaAs layers grown by metalorganic vapour phase epitaxy from TMGa and TBAs

Abstract

In this work the possibility of controlling carbon intrinsic-doping in GaAs homoepitaxial layers grown by metalorganic vapour phase epitaxy (MOVPE) from the trimethyl-gallium (TMGa) and tertiary-buthylarsine (TBAs) precursors was evaluated via the analysis of transport properties as a function of the growth parameters and for two substrates mis-orientations; Hall effect measurements were performed on the samples as a function of temperature. Intrinsically p-doped GaAs layers were obtained with a hole concentration in the range (10 14 -10 18 ) cm -3 and a corresponding RT mobility in the range (100 -400) cm 2 /Vs. The simultaneous analysis of the Hall free hole density and Hall mobility yielded the effective doping level, the compensation ratio and the thermal ionisation energy of the acceptor impurity as a function of the growth parameters.

Zinc doped GaAs epitaxial layers MOVPE grown by liquid metalorganic sources

“…1 and 2, respectively; a similar investigation for the Carbon intrinsically doped samples has already been published and discussed [12,13]. Just below RT, the usual transport into the valence band is dominant, whereas the low temperature electrical data indicate the activation impurity band conduction, consistently with the photoluminescence investigation discussed in the following.…”

“…When the doping overcomes the level of about 10 18 cm -3 , p(T) and µ(T) curves become T-independent, as for a degenerate hole gas. A simultaneous fit of mobility and hole density data was performed as described in [12,13], for conduction through the extended states. The usual scattering mechanisms and the Wiley approach to treat the valence band complexity were considered: to our knowledge, only a few works in the literature have been devoted to the fitting of the electrical data vs. temperature in GaAs:Zn samples [16].…”

“…On the other hand, in the case of extrinsic doping, limitations related to compensation effects, hydrogen passivation and low lifetime for minority carriers, have been reported when Carbon tetrabromide (CBr 4 ) or Carbon tetrachloride (CCl 4 ) are used [10]; however, in the intrinsic Carbon doping, some drawbacks related to the surface morphology of heavily doped layers have been reported [11]. We have previously demonstrated that it is possible to control the intrinsic Carbon doping in MOVPE grown GaAs layers by using trimethyl gallium (TMGa) and the less hazardous, high-purity As source tertiary buthyl arsine (TBAs) [12,13] in a wide range of hole concentrations (between 10 14 and 10 18 cm -3 ). In this work, we present an analysis of the electrical and optical quality of p-doped GaAs layers, MOVPE grown by TMGa and TBAs, extrinsically doped by Zinc.…”

Anomalies in the Temperature Dependence of the Photoelectrical Response of GaAs/InGaP Superlattices

“…Other details about the growth and the structural and optical properties of the samples are reported elsewhere. [13][14][15][16] In order to perform electrical measurements, an extended AuGeNi ohmic contact was fabricated on the backside of the n þ GaAs substrate whereas AuZn dot contacts, 400 mm in diameter, were deposited on the p þ GaAs cap layer. Finally, a pattern of mesa structures, 6 mm in depth, was obtained by a 6 min etching in a HCl-…”