Selective oxidation of aluminum-bearing III-V semiconductors: Properties and applications to quantum well heterostructure lasers and transistor devices

In this work, the water vapor oxidation of Al-bearing III-V compound semiconductors is used to fabricate light-emitting and electronic devices. High Al-composition heterostructure crystals such as Al$\sb{\rm x}$Ga$\sb{\rm 1-x}$As (x $\sbsp{\sim}{>}$ 0.5) are converted into a stable native oxide at moderately elevated temperatures ($\sbsp{\sim}{>}400\ \sp\circ$C) in a water vapor saturated ambient. Dependence of the oxidation process on Al composition makes possible the formation of embedded oxide layers in between semiconductor crystal using selective (lateral) oxidation. Data are presented showing how various growth parameters, crystal layering, and oxidation times and temperatures affect the lateral oxidation process. Etch studies of superlattice structures that are Zn-diffused and oxidized are also presented showing that the water vapor oxidation process behaves similarly to chemical wet etches.Native oxide-based AlGaAs-GaAs metal-oxide-semiconductor field-effect transistor devices are fabricated via lateral oxidation of a thin AlAs layer. Data are presented demonstrating depletion-mode transistor operation. This shows that the native oxide is of sufficient quality to allow modulation of an underlying GaAs channel.Impurity-induced layer disordering (IILD) and water vapor oxidation are also used to define a planar minidisk cavity in a superlattice (70 A AlAs + 30 A GaAs) crystal. Data are presented showing photopumped "whispering gallery mode" laser operation of $\sim$37 $\mu$m minidisks lasers. Finally, the IILD and oxidation process is extended to the formation of a microdisk photonic lattice. Data are presented showing that the microdisks ($\sim$9 $\mu$m diameter) are sufficiently coupled to form "bands" in the photopumped recombination radiation spectra.Ope