Improvement of p-type GaAs0.51Sb0.49 metal-oxide-semiconductor interface properties by using ultrathin In0.53Ga0.47As interfacial layers

The effects of interfacial In0.53Ga0.47As layers on Al2O3/GaAs0.51Sb0.49 metal-oxide-semiconductor (MOS) structures on InP substrates have systematically been studied. It is found that the interfacial InGaAs layers can reduce Dit values of the Al2O3/GaAsSb MOS interfaces down to 3–4 × 1011 cm−2 eV−1, which is almost one order of the magnitude lower than in the MOS interfaces without any InGaAs interfacial layers. It is also found that the InGaAs thickness of 1.0–1.5 nm is sufficient to reduce Dit to this low value. In order to obtain these results, the influence of an additional parasitic conductance and capacitance related to the GaAsSb/InP heterointerface needs to be considered, because the C-V characteristics of Al2O3/GaAs0.51Sb0.49/InP MOS capacitors in the accumulation region exhibit strong frequency dispersion, regardless of the InGaAs interfacial layer. We present through simulation of the C-V characteristics using a 2-dimensional device simulator that the correction of this series resistance and capacitance by using an equivalent circuit model can effectively eliminate the influence of the potential barrier at the GaAsSb/InP heterointerface from the experimental C-V ones, allowing us to employ the conventional conductance method for extracting interface trap density (Dit).The effects of interfacial In0.53Ga0.47As layers on Al2O3/GaAs0.51Sb0.49 metal-oxide-semiconductor (MOS) structures on InP substrates have systematically been studied. It is found that the interfacial InGaAs layers can reduce Dit values of the Al2O3/GaAsSb MOS interfaces down to 3–4 × 1011 cm−2 eV−1, which is almost one order of the magnitude lower than in the MOS interfaces without any InGaAs interfacial layers. It is also found that the InGaAs thickness of 1.0–1.5 nm is sufficient to reduce Dit to this low value. In order to obtain these results, the influence of an additional parasitic conductance and capacitance related to the GaAsSb/InP heterointerface needs to be considered, because the C-V characteristics of Al2O3/GaAs0.51Sb0.49/InP MOS capacitors in the accumulation region exhibit strong frequency dispersion, regardless of the InGaAs interfacial layer. We present through simulation of the C-V characteristics using a 2-dimensional device simulator that the correction of this series resistance and c...