Role of vanadium in organometallic vapor phase epitaxy grown GaAs

Abstract

The electrical and photoluminescent properties of vanadium incorporated into GaAs epitaxial layers from a VO(OC2H5)3 source during organometallic vapor phase epitaxy were examined. The vanadium concentration in the GaAs was controllably varied from 1016 to 1018 atoms cm−3. Deep level transient spectroscopy showed the presence of an electron trap at Ec−0.15 eV which increased in concentration with vanadium content of the epitaxial layers. A maximum value of 8×1015 cm−3 for this trap was obtained. There were no midgap electron traps associated with vanadium. In intentionally Si-doped epitaxial layers, co-doping with vanadium was observed to have no effect in reducing the carrier density when the Si concentration was ≥4×1016 cm−3. The net carrier concentration profiles resulting from 29Si implantation into GaAs containing 1018 cm−3 of total V had sharper tails than for similar implantation into undoped material, indicating the presence of less than 1016 cm−3 V-related acceptors. Photoluminescent spectra exhibited the characteristic V+3 intracenter emission at 0.65–0.75 eV. No other deep level photoluminescence was detected. For a V concentration of 1016 cm−3 only 2.5×1013 cm−3 was electrically active. Over the entire V concentration investigated this impurity was predominantly (≥99%) inactive.

A study of deep levels in vanadium-doped GaAs grown by OMVPE

“…The DLTS spectrum of sample B shows a wellpronounced peak around 90 K, labelled E1. We detected this E1 trap for different V concentrations, its amplitude increasing with the V concentration and reaching a maximum value of about 10 16 cm −3 for a V concentration of 2 × 10 18 cm −3 , in agreement with a previous report [11]. This observation indicates that the E1 defect is most likely associated with V doping.…”

“…According to Akayama et al [10], and Terao et al [7], an oxygen-containing organometallic V precursor is needed to obtain SI material by VPE or OMVPE. However, Hobson et al found results in contradiction with this last conclusion [11]. Although they have used the same oxygen-containing precursor as that used by Akayama et al, VO(OC 2 H 5 ) 3 , they did not obtain a SI material by OMVPE.…”

Semi-Insulating Transition Metal-Doped III-V Materials

“…Thus, vanadium plays a mainly chemical role (gettering of donors) during the crystal growth process [30]. Recent MOVPE growth of V-doped GaAs [31] has confirmed this interpretation. It was shown that only less than 1% of vanadium atoms in GaAs MOVPE layers are electrically active.…”

“…It was shown that only less than 1% of vanadium atoms in GaAs MOVPE layers are electrically active. Furthermore, attempts to create a V-related complex (suggested by many authors) by implantation into GaAs of V, O, V+O, Si+V+O, and S+V+O, for variety of doses and at different energies, have led to an unequivocally negative result [31] .…”

Photoluminescence Excitation Spectroscopy of MOCVD-Grown: GaAs:V

“…The ultra-high-purity VO(OC 2 H5) 3 source was held at 10'C in a thermostatic bath. The detailed processes of the growth and chemical analysis were described in a previous report [5]. Some of the samples were additionally doped with Si and/or Be in order to systematically vary the Fermi levels in the epitaxial layer and change the charge state of the vanadium.…”