Yueh Chin Lin

Electrical Characteristics of n, p-In 0.53 Ga 0.47 As MOSCAPs With In Situ PEALD-AlN Interfacial Passivation Layer

The effects of plasma enhanced atomic layer deposition (PEALD)-AlN interfacial passivation layer (IPL) on the Al₂O₃/In_0.53Ga_0.47As interfaces qualities are studied with different plasma powers. The improvement in electrical properties, including capacitance-voltage (C-V) hysteresis, frequency dispersion, and interface state densities (Dit) are demonstrated on the Al₂O₃/n, p-In_0.53Ga_0.47As MOS capacitors. The excellent C-V behaviors are observed on both type of In_0.53Ga_0.47As-based MOS devices by performing a thin AlN-IPL at the plasma power of 150 W. To explore the interaction between PEALD-AlN layer and In_0.53Ga_0.47As surface, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy analyses have also been characterized.

Plasma Enhanced Atomic Layer Deposition Passivated HfO 2 /AlN/In 0.53 Ga 0.47 As MOSCAPs With Sub-Nanometer Equivalent Oxide Thickness and Low Interface Trap Density

The impact of in situ plasma-enhanced atomic layer deposition passivation on the electrical properties of HfO₂/In_0.53Ga_0.47As metal-oxide-semiconductor capacitors (MOSCAPs) has been studied. Excellent interface quality of high-<i>k</i>/III-V is achieved by aluminum nitride (AlN) interfacial passivation layer, including strong inversion behaviors and unpinned Fermi level. The band alignment of HfO₂/AlN/In_0.53Ga_0.47As structure with the valence band offsets of 2.81 ± 0.1 eV and the conduction band offsets of 1.9 ± 0.1 eV was obtained. Better interface and optimized high-<i>k</i> dielectric qualities are achieved using post remote-plasma treatment with either N₂/H₂ or NH₃ gases. Sub-nanometer equivalent oxide thickness HfO₂/AlN/In_0.53Ga_0.47As MOSCAPs with low interface trap density and low leakage current density have been characterized.

Band Alignment Parameters of Al2O3/InSb Metal-Oxide-Semiconductor Structure and Their Modification with Oxide Deposition Temperatures

From the Fowler–Nordheim (FN) current–voltage (I–V) characteristic and X-ray photoelectron spectroscopy (XPS) analysis, the conduction band offset of 2.73±0.1 eV and the valence band offset of 3.76±0.1 eV have been extracted for the atomic-layer-deposition (ALD) Al2O3/InSb structure. By these analyses, the parameters of an Al2O3 film including bandgap, electron affinity, and electron effective mass are also deduced. The capacitance–voltage and I–V characteristics of ALD Al2O3/InSb at different deposition temperatures indicate the modification of the Fermi level in InSb to 0.09 eV lower than that in metal side of the sample deposited at 250 °C as compared to the samples deposited at lower temperatures.

Effects of In-Situ Plasma-Enhanced Atomic Layer Deposition Treatment on the Performance of HfO 2 /In 0.53 Ga 0.47 As Metal–Oxide–Semiconductor Field-Effect Transistors

In-situ plasma-enhanced atomic layer deposition (PEALD) technique was employed for device passivation to realize a high-performance inversion-mode HfO2/In0.53Ga0.47As metal-oxide-semiconductor field-effect transistor (MOSFET). Excellent quality of gate dielectric is enabled by utilizing the PEALD-aluminum nitride as a pre-gate interfacial layer, followed by a post-gate remote-plasma gas treatment. In-situ PEALD treatment led to enhanced dc characteristics, such as drain current, peak transconductance, subthreshold swing, OFF leakage current, and effective electron mobility. X-ray photoelectron spectroscopy analysis indicates a reduction of In- and Ga-related signals. Furthermore, small drain current hysteresis and low-interface state density (Dit) value confirm a high interfacial quality for the high-k/III-V structure. Overall, the PEALD passivation for HfO2/In0.53Ga0.47As interface shows a remarkable improvement on the MOSFET performance.

Impact of AlN Interfacial Dipole on Effective Work Function of Ni and Band Alignment of Ni/HfO 2 /In 0.53 Ga 0.47 As Gate-Stack

AlN has successfully been applied to passivate the oxide/III-V interface; however, it changes both the metal work function (WF) and band alignment of the gate-stack and, thus, affects the power consumption of the devices. We found that the AlN layer induces a dipole δ = 0.18 eV between HfO2 and substrate. The dipole value obtained from capacitance- voltage characteristics performs good agreement with the results of X-ray photoelectron spectroscopic measurements. The effective WF of Ni is found to be 5.55 eV, which is larger than its WF in vacuum. The valance band offset and the conduction band offset of HfO2 with AlN/In0.53Ga0.47As are found to be 2.82 and 2.06 eV, respectively.

Electrical Characterization and Materials Stability Analysis of

In this letter, a high-k composite oxide composed of La₂O₃ and HfO₂ is investigated for n-In_0.53Ga_0.47As metal-oxide-semiconductor (MOS) capacitor application. The composite oxide was formed by depositing five layers of La₂O₃(0.8 nm)/HfO₂(0.8 nm) on InGaAs with post deposition annealing at 500°C. The MOS capacitors fabricated show good inversion behavior, high capacitance, low leakage current, with excellent interface trap density (D_it) of 7.0×10¹¹ cm^-2eV^-1, small hysteresis of 200 mV and low capacitance equivalent thickness of 2.2 nm at 1 kHz were also achieved.

{\rm La}_{2}{\rm O}_{3}/{\rm HfO}_{2}

Accurate determination of the flat band voltage (VFB) is very important for extracting the effective work function of metal, and it will affect the prediction of the threshold voltage of the metal-oxide-semiconductor (MOS) devices. A modified method to accurately determine VFB of the In0.53Ga0.47As n-type MOS device is presented. The effects of capacitance voltage hysteresis and interface trap density at the oxide/semiconductor interface on the accuracy of the extracted VFB values are discussed. The results are also applicable to other MOS devices with high mobility channel materials.

Composite Oxides on n-

This study investigates the time-dependent dielectric breakdown (TDDB) characteristics of La2O3/HfO2 and HfO2/La2O3 stacking layers on an n-In0.53Ga0.47As metal–oxide–semiconductor capacitor. Both designs improved the reliability compared with a single layer of HfO2. The TDDB followed the thermochemical E model. The current transportation mechanism changed from thermionic emission to Frenkel–Poole emission because of the traps creation under voltage stress. Both designs resulted in similar lifespans and voltage accelerating factors. However, the La2O3/HfO2 design had a longer lifespan because of the lower interface trap density and insertion of the HfO2 diffusion barrier layer between La2O3 and n-In0.53Ga0.47As. The oxide stacks exhibited excellent reliability and achieved a lifespan of 28.4 years.

{\rm In}_{0.53}{\rm Ga}_{0.47}{\rm As}

GaSb epitaxial layers were directly grown on GaAs substrates by metal–organic chemical vapor deposition involving Sb interfacial treatment with optimized growth temperature and V/III ratio. The interfacial treatment effectively reduces the surface energy and strain energy difference, resulting in a quasi-2D growth mode. When the GaSb layer was grown at 520 °C, the strain induced by lattice mismatch was accommodated by 90° dislocations with a period of 5.67 nm. By optimizing the V/III ratio, the surface roughness of the ultrathin GaSb/GaAs heterostructure was reduced, resulting in a reduced carrier scattering and improved electronic properties.

MOS Capacitors With Different Annealing Temperatures

Optimizing surface morphology of ohmic contacts on GaN high electron mobility transistors continues to be a challenge in the GaN electronics industry. In this study, a variety of metal schemes were tested under various annealing conditions to obtain contacts with optimal qualities. A Ti/Al/Ti/Ni/Au (20/120/40/60/50u2009nm) metal scheme demonstrated the lowest contact resistance (Rc) and a smooth surface morphology, and the mechanisms were investigated by materials analysis. A Ti/Al/Ti/Ni/Au metal scheme with optimized Ti and Ni thicknesses can result in formation of a larger proportion of Al-Ni intermetallics and a continuous TiN interlayer, which results in smooth surface and low Rc.