The inversion behaviors of atomic-layer-deposition Al2O3/n-In0.53Ga0.47As metal-oxide-semiconductor capacitors are studied by various surface treatments and postdeposition annealing using different gases. By using the combination of wet sulfide and dry trimethyl aluminum surface treatment along with pure hydrogen annealing, a strong inversion capacitance-voltage (C-V) response is observed, indicating a remarkable reduction in interface trap state density (Dit) at lower half-part of In0.53Ga0.47As band gap. This low Dit was confirmed by the temperature independent C-V stretch-out and horizontal C-V curves. The x-ray photoelectron spectroscopy spectra further confirm the effectiveness of hydrogen annealing on the reduction of native oxides.

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The influences of surface treatment and gas annealing conditions on the inversion behaviors of the atomic-layer-deposition Al2O3/n-In0.53Ga0.47As metal-oxide-semiconductor capacitor

A capacitance model is developed and a correction formula is derived to reconstruct the intrinsic oxide capacitance value from measured capacitance and conductance of lossy MOS devices. Due to discrepancies during processing, such as cleaning, an unwanted lossy dielectric layer is present in the oxide/semiconductor interface causing the measured capacitance in strong accumulation to be frequency dependent. The capacitance–voltage characteristics after correction are free from any frequency dispersion effect and give the actual oxide thickness in accumulation at all frequencies. Simulation of the measured capacitance–frequency curve was carried out using the model. The model was applied to SiO2/Si, SiO2/strained Si and GaO2/GaAs MOS capacitors.

A model for capacitance reconstruction from measured lossy MOS capacitance–voltage characteristics

Novel Ga2O3 (Ga2O3) passivation techniques to produce low Dit oxide-GaAs interfaces

InAs is very attractive as a channel material for high-speed metal-oxide-semiconductor (MOS) field-effect transistors due to its very high electron mobility and saturation velocity. We investigated the processing conditions and the interface properties of an InAs metal-oxide-semiconductor structure with Al2O3 dielectric deposited by atomic-layer deposition. The MOS capacitor I-V and C-V characteristics were studied and discussed. Simple field-effect transistors fabricated on an InAs bulk material without source/drain implantation were measured and analyzed.

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Properties of InAs metal-oxide-semiconductor structures with atomic-layer-deposited Al2O3 Dielectric

We have developed III-V-semiconductor-on-insulator (III-V-OI) structures on Si wafers with excellent bottom interfaces between In0.53Ga0.47As-OI channel layers and atomic-layer-deposited Al2O3 (ALD-Al2O3) buried oxides (BOXs). A surface activated bonding process and the sulfur passivation pretreatment have realized the excellent In0.53Ga0.47As-OI/ALD-Al2O3 BOX bottom interface properties. As a result, the III-V-OI n-channel metal-insulator-semiconductor field-effect transistors under the back-gate configuration showed the peak mobility of 1800 cm2/V s and the higher electron mobility than the Si universal one even in the high effective electric field range because of the reduction in the surface roughness and fixed charges.

III-V-semiconductor-on-insulator n-channel metal-insulator-semiconductor field-effect transistors with buried Al2O3 layers and sulfur passivation: Reduction in carrier scattering at the bottom interface

Interface properties of Ga 2 O 3 GaAs structures fabricated using in-situ multiple-chamber molecular beam epitaxy have been investigated. The oxide films were deposited on clean, atomically ordered (100) GaAs surfaces at ≅600°C by electron-beam evaporation using a Gd 3 Ga 5 O 12 single-crystal source. Metal-oxide-semiconductor (MOS) capacitors were characterized by quasi-static capacitance voltage ( C - V ) as well as by C - V and conductance voltage ( G - V ) measurements at frequencies ranging from 100 Hz to 1 MHz. A midgap interface state density D it in the low 10 10 cm −2 eV −1 range has been inferred from C - V measurements using the quasi-static/high frequency technique. Although interface trap loss is almost entirely masked by oxide loss, a wide bottom of the D it - E characteristic extending from E v + 0.27 eV to E c − 0.19 eV has been concluded from G - V measurements. The formation of inversion layers in both n - and p -type GaAs has been clearly established.

M. Passlack

Papers

C-V and G-V characterization of in-situ fabricated Ga2O3GaAs interfaces for inversion/accumulation device and surface passivation applications