\textit{In-situ} MBE and ALD deposited HfO$_{2}$ on In$_{0.53}$Ga$_{0.47}$As*

The semiconductor industry is calling for innovative devices offering high performance with low power consumption. High-$\kappa $ dielectrics/metal gates on high carrier mobility channels are now strong contenders in the post Si CMOS application. Hafnium-based oxide has been employed as the gate dielectric in Si CMOS since 45 nm node and InGaAs is a leading candidate for channel materials. However, reports of HfO$_{2}$ on InGaAs are scant, and surface treatments using H$_{2}$S or trimethylaluminum are claimed to be required for achieving high quality HfO$_{2}$(high-$\kappa )$/InGaAs interface. In this work, HfO$_{2}$ has been \textit{in-situ} deposited on $n$- and $p$-In$_{0.53}$Ga$_{0.47}$As using both molecular-beam-epitaxy (MBE) and atomic-layer- deposition (ALD), without using any interfacial passivation layer or surface treatments. The HfO$_{2}$/In$_{0.53}$Ga$_{0.47}$As metal-oxide-semiconductor capacitors (MOSCAPs) all exhibit outstanding thermal stabilities ($>$ 800$^{\circ}$C), low leakage currents ($\sim $ 10$^{-8}$ A/cm$^{2}$ at 1 MV/cm), and good CV characteristics. Moreover, the MOSCAPs have shown spectra of interfacial trap densities (D$_{it}$'s) with no discernible peaks at mid-gap, confirmed by temperature-dependent conductance method.