M. B. Santos

In0.53Ga0.47As based metal oxide semiconductor capacitors with atomic layer deposition ZrO2 gate oxide demonstrating low gate leakage current and equivalent oxide thickness less than 1nm

The paper demonstrates properties of metal oxide semiconductor capacitors fabricated on molecular beam epitaxial In0.53Ga0.47As wafers with the atomic layer deposition ZrO2 gate oxide. The equivalent oxide thickness of 0.8nm was obtained for 5nm thick ZrO2, while the gate leakage current density at VFB+1V was as low as 0.1A∕cm2. Sensitivity of capacitance-voltage characteristics to the metal gate work function along with low frequency dispersion of ∼5%/decade served as a strong evidence of a nonpinned Fermi level at the oxide-InGaAs interface. Both electrical and structural properties remain stable up to 800°C.

Self-aligned n-channel metal-oxide-semiconductor field effect transistor on high-indium-content In0.53Ga0.47As and InP using physical vapor deposition HfO2 and silicon interface passivation layer

In this work, we present the electrical and material characteristics of TaN∕HfO2∕In0.53Ga0.47As and InP substrate metal-oxide-semiconductor capacitors and self-aligned n-channel metal-oxide-semiconductor field effect transistor (n-MOSFET) with physical vapor deposition Si interface passivation layer. Excellent electrical characteristics, thin equivalent oxide thickness (∼1.7nm), and small frequency dispersion (<2%) were obtained. n-channel high-k InGaAs- and InP-MOSFETs with good transistor behavior and good split capacitance-voltage (C-V) characteristics on In0.53Ga0.47As and InP substrates have also been demonstrated.

A study of metal-oxide-semiconductor capacitors on GaAs, In0.53Ga0.47As, InAs, and InSb substrates using a germanium interfacial passivation layer

In this letter, we present electrical characteristics of HfO2-based metal-oxide-semiconductor capacitors (MOSCAPs) on n- and p-type GaAs, In0.53Ga0.47As, InAs, and InSb substrates, along with the effect of a thin germanium interfacial passivation layer. We found that MOSCAPs on all n-type substrates showed good C-V characteristics with small frequency dispersion (<10% and <200 mV). However, MOSCAPs on p-type GaAs and In0.53Ga0.47As substrates exhibited poor C-V characteristics implying severe Fermi level pinning, as has also been seen for p-type InP substrate. On the other hand, MOSCAPs on p-type InAs and InSb substrates, known as smaller bandgap materials, showed good C-V characteristics. We also present plausible mechanism for Fermi level pinning and interface characteristics.

A high performance In0.53Ga0.47As metal-oxide-semiconductor field effect transistor with silicon interface passivation layer

In this letter, we demonstrate a high performance In0.53Ga0.47As channel n-type metal-oxide-semiconductor field effect transistor with silicon interface passivation layer (IPL) and HfO2 gate oxide. Owing to the effectiveness of Si IPL on improving the interface quality, good device characteristics have been obtained, including the peak transconductance of 7.7 mS/mm (Lg=5 μm and Vd=50 mV), drive current of 158 mA/mm (Lg=5 μm, Vgs=Vth+2 V, and Vd=2.5 V), and the peak effective channel mobility of 1034 cm2/V s. As an important factor on device design, the impact of silicon IPL thickness on the transistor characteristics has been investigated.

High mobility HfO2-based In0.53Ga0.47As n-channel metal-oxide-semiconductor field effect transistors using a germanium interfacial passivation layer

The electrical characteristics of HfO2-based n-channel metal-oxide-semiconductor field effect transistors (MOSFETs) and metal-oxide-semiconductor capacitors (MOSCAPs) on high indium content In0.53Ga0.47As channel layers are presented. N-channel MOSFETs with a germanium (Ge) interfacial passivation layer (IPL) show maximum mobility 3186 cm2/V s from split capacitance-voltage (C-V) method and the normalized drain current (to the channel length of 1 μm) of 753 mA/mm at Vg=Vth+2 V and Vd=2 V. On the contrary, MOSFETs without a Ge IPL or with high temperature post-metal annealing (PMA) exhibit inferior characteristics. MOSCAPs on n-type In0.53Ga0.47As layers demonstrate excellent C-V characteristics including low C-V frequency dispersion and low dielectric leakage current.

Resistively detected nuclear magnetic resonance via a single InSb two-dimensional electron gas at high temperature

We report on the demonstration of the resistively detected nuclear magnetic resonance (RDNMR) of a single InSb two-dimensional electron gas (2DEG) at elevated temperatures up to 4 K. The RDNMR signal of I115n in the simplest pseudospin quantum Hall ferromagnet triggered by a large direct current shows a peak-dip line shape, where the nuclear relaxation time T1 at the peak and the dip is different but almost temperature independent. The large Zeeman, cyclotron, and exchange energy scales of the InSb 2DEG contribute to the persistence of the RDNMR signal at high temperatures.

High Electron Mobility (2270 cm 2 /Vsec) In 0.53 Ga 0.47 As Inversion Channel N-MOSFETs with ALD ZrO 2 Gate Oxide Providing 1 nm EOT

Self-aligned MOSFETs with high-Indium content InGaAs based channel, ultra-thin high-k dielectric and metal gate are attractive devices for logic applications. To be compatible with the future generation CMOS technology, these devices must demonstrate high channel mobility and excellent performance at low operating voltage. Development of a thermally stable I-V/high-k interface with low EOT and low interface state density remains the key challenge for compound semiconductor implementation.

Gate depletion of an InSb two-dimensional electron gas

We investigated the gate control of a two-dimensional electron gas (2DEG) confined to InSb quantum wells with an Al2O3 gate dielectric formed by atomic layer deposition on a surface layer of Al0.1In0.9Sb or InSb. The wider bandgap of Al0.1In0.9Sb compared to InSb resulted in a linear, sharp, and non-hysteretic response of the 2DEG density to gate bias in the structure with an Al0.1In0.9Sb surface layer. In contrast, a nonlinear, slow, and hysteretic (nonvolatile-memory-like) response was observed in the structure with an InSb surface layer. The 2DEG with the Al0.1In0.9Sb surface layer was completely depleted by application of a small gate voltage (∼ −0.9 V).

Nonlinear magnetic field dependence of spin polarization in high-density two-dimensional electron systems

The spin polarization (P) of high-density InSb two-dimensional electron systems (2DESs) has been measured using both parallel and tilted magnetic fields. P is found to exhibit a superlinear increase with the total field B. This P-B nonlinearity results in a difference in spin susceptibility between its real value s and gm / m g (m and g are the effective mass and g factor, respectively) as routinely used in experiments. We demonstrate that such a P-B nonlinearity originates from the linearly P-dependent g due to the exchange coupling of electrons rather than from the electron correlation as predicted for the low-density 2DES.

Effects of Anneal and Silicon Interface Passivation Layer Thickness on Device Characteristics of In0.53Ga0.47As Metal-Oxide-Semiconductor Field-Effect Transistors

In this letter, we demonstrate an In 0.53 Ga 0.47 As channel n-type metal-oxide-semiconductor field-effect transistor (MOSFET) with silicon interface passivation layer (IPL) and HfO 2 gate oxide. The effects of the source/drain activation temperature, postdeposition annealing temperature, and thickness of silicon IPL on the transistor characteristics have been investigated. The results suggest that the annealing temperatures are critical for determining the transistor performances. Even though In 0.53 Ga 0.47 As is easier to obtain the unpinned surface Fermi level compared to GaAs, applying silicon IPL still improves the In 0.53 Ga 0.47 As nMOSFET characteristics significantly through engineering the HfO 2 /In 0.53 Ga 0.47 As interface quality.