Varistha Chobpattana

Nitrogen-passivated dielectric/InGaAs interfaces with sub-nm equivalent oxide thickness and low interface trap densities

We report on the electrical characteristics of HfO2 and HfO2/Al2O3 gate dielectrics deposited on n-In0.53Ga0.47As by atomic layer deposition, after in-situ hydrogen or nitrogen plasma surface cleaning procedures, respectively. It is shown that alternating cycles of nitrogen plasma and trimethylaluminum prior to growth allow for highly scaled dielectrics with equivalent oxide thicknesses down to 0.6 nm and interface trap densities that are below 2.5 × 1012 cm−2 eV−1 near midgap. It is shown that the benefits of the nitrogen plasma surface cleaning procedure are independent of the specific dielectric.

Frequency dispersion in III-V metal-oxide-semiconductor capacitors

A recombination-controlled tunneling model is used to explain the strong frequency dispersion seen in the accumulation capacitance and conductance of dielectric/n-In0.53Ga0.47As metal-oxide-semiconductor capacitors. In this model, the parallel conductance is large when, at positive gate biases, the metal Fermi level lines up with a large density of interface states in the In0.53Ga0.47As band gap. It is shown that the model explains in a semi-quantitative manner the experimentally observed capacitor characteristics, including a peak in parallel conductance/frequency (Gp/ω) versus log frequency curves at positive gate bias and the dependence of the frequency dispersion on the dielectric thickness.

Influence of gate metallization processes on the electrical characteristics of high-k/In0.53Ga0.47As interfaces

The influence of different gate metal deposition processes on the electrical characteristics of dielectric/III-V interfaces is investigated. Al2O3 and HfO2 dielectrics are grown on In0.53Ga0.47As channels and top metal electrodes are deposited by either thermal evaporation or electron beam deposition. It is shown that metal-oxide-semiconductor capacitors with electron beam evaporated electrodes exhibit substantially larger midgap interface trap densities than those with thermally evaporated electrodes. The damage caused by electron beam metallization can be mitigated by subsequent, long anneals in forming gas.

0.5 V Supply Voltage Operation of In 0.65 Ga 0.35 As/GaAs 0.4 Sb 0.6 Tunnel FET

In this letter, we demonstrate using fast current-voltage measurements, low switching slope of 64 mV/decade over a drain current range between

Al-doped HfO2/In0.53Ga0.47As metal-oxide-semiconductor capacitors

10^{\mathrm {\mathbf {-3}}}

Influence of plasma-based in-situ surface cleaning procedures on HfO2/In0.53Ga0.47As gate stack properties

and

Highly Scalable Raised Source/Drain InAs Quantum Well MOSFETs Exhibiting

2 \times 10^{\mathrm {\mathbf {-2}}} \mu

I_{{\scriptstyle {\rm ON}}}=482~\mu{\rm A}/\mu{\rm m}

A/

at

\mu

I_{{\scriptstyle {\rm OFF}}}=100~{\rm nA}/\mu{\rm m}

m in staggered-gap In0.65Ga0.35As/GaAs0.4Sb0.6 tunneling field-effect transistors (TFETs) at