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In-Sn-Zn oxide (ITZO) nanocomposite films have been investigated extensively as a potential material in thin-film transistors due to their good electrical properties. In this work, ITZO thin films were deposited on glass substrates by high-power impulse magnetron sputtering (HiPIMS) at room temperature. The influence of the duty cycle (pulse off-time) on the microstructures and electrical performance of the films was investigated. The results showed that ITZO thin films prepared by HiPIMS were dense and smooth compared to thin films prepared by direct-current magnetron sputtering (DCMS). With the pulse off-time increasing from 0 μs (DCMS) to 2000 μs, the films’ crystallinity enhanced. When the pulse off-time was longer than 1000 μs, In2O3 structure could be detected in the films. The films’ electrical resistivity reduced as the pulse off-time extended. Most notably, the optimal resistivity of as low as 4.07 × 10−3 Ω·cm could be achieved when the pulse off-time was 2000 μs. Its corresponding carrier mobility and carrier concentration were 12.88 cm2V−1s−1 and 1.25 × 1020 cm−3, respectively.

Thermo-elastic strain is induced by through silicon vias (TSV) due to the difference of thermal expansion coefficients between the copper (∼18 ppm/◦C) and silicon (∼2.8 ppm/◦C) when the structure is exposed to a thermal budget in the three dimensional integrated circuit (3DIC) process. These thermal expansion stresses are high enough to induce the delamination on the interfaces between the copper, silicon, and isolated dielectric. A compact analytic model for the strain field induced by different layouts of thermal copper filled TSVs with the linear superposition principle is found to result in large errors due to the strong stress interaction between TSVs. In this work, a nonlinear stress analytic model with different TSV layouts is demonstrated by the finite element method and Mohr’s circle analysis. The stress characteristics are also measured by the atomic force microscope-raman technique at a nanometer level resolution. This nonlinear stress model for the strong interactions between TSVs results in an electron mobility change ~2-6% smaller than that resulting from a model that only considers the linear stress superposition principle.

Positron Annihilation Spectra (PAS), Raman, and photoluminescence spectroscopy reveal that Si0.5Ge0.5/Si interface quality can be dramatically improved through a low energy plasma cleaning process using hydrogen. In the PAS, the particularly small values of lifetime and intensity near the Si0.5Ge0.5/Si interface in the treated sample indicate a 2.25 times reduction in defect concentration. Fewer defects were found in the interface, resulting in a high compressive strain of about 0.36 % in the top layer, which can be observed in Raman spectra, and a 1.39 times increase to the radiative recombination rate for the infrared emission, which can be observed in the photoluminescence spectra. Improved Si0.5Ge0.5/Si interface quality leads to improved optical and electrical characteristics in SiGe-based devices in a broader range of photovoltaic applications. The PAS is also shown to be a useful metrology tool for quantifying defects in SiGe-based devices.

Serious wafer curvature and residual stress are formed during the growth of an epi-GaN layer on Sapphire substrates due to the different thermal expansion coefficients in these two materials. By using theoretical analysis and a simulation model using the finite element method to describe the realistic shape of wafer curvature on epi-GaN wafers, we examine the influence which different thickness and thermal expansion coefficients in the top epi-GaN layer have on wafer curvature reduction. In addition a new process to reduce wafer curvature and to relax residual stress is proposed. With an additional laser treatment on a sample surface after the growth of the top epi-GaN layer on a Sapphire substrate has taken place, the wafer curvature can be reduced to ~ 37 mm from the original ~ 45 mm in 2 inch wafers with an optimized surface structure design.

The stress simulation with the three-dimensional (3-D) boundary effects and their impact on the transistor performance are described. The ultrahigh compressive stress contact-etching-stop layer (CESL) stressor, SiGe source-drain (S/D) stressor with high Ge concentration and optimal design in device dimensions has achieved the high-performance pFET.

The tunneling current of Pt/oxide/n-6H-SiC tunneling diodes is used for electroluminescence (EL) and the blue EL at room temperature is seen at negative gate bias. The donor-acceptor pair (DAP) transition is increased by the electric field due to carrier tunneling and hence strong luminescence is seen at negative bias, while no luminescence is seen at positive bias.

The material and electrical modification of HF-based dielectrics at different annealing conditions and different Si incorporations is investigated. The X-ray photoelectron spectroscopy (XPS) results have indicated a great signature of the formation of a HF-silicate layer.

Transmission line pulse measurements are utilized to study the reliability of the Hf[O.sub.2] dielectric under an electrostatic discharge event. The field acceleration parameter of the Hf[O.sub.2] dielectric which are smaller than that of the silicon oxynitride in the high-field stress regime could be attributed to the stronger phonon-assisted tunneling process in the high-k dielectrics.

The structural and electrical characteristics of hafnium oxide (HfO2) gate dielectrics treated by a variety of post-deposition nitridation processes, including remote N2, N2/H2 and NH3 plasma, are presented by the x-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy and electrical measurements. The XPS measurement reveals that the nitrogen content in the HfO2 thin film treated by remote nitrogen and hydrogen plasma is higher than that treated only by remote nitrogen plasma, suggesting that the hydrogen has the capability to facilitate nitrogen dissociation. An ultra-thin interfacial layer (IL) thickness (~0.3 nm), a high dielectric constant (20), an acceptable gate leakage current density (~9 × 10-6 Acm-2), and a low capacitance equivalent thickness (1.9 nm) of the HfO2 gate dielectric were achieved by the post-deposition remote NH3 plasma nitridation treatment. However, an IL layer as thick as 1.5 nm was observed in the sample treated only by remote N2 plasma. The results indicate that the participation of hydrogen in the nitridation process is a promising way to improve the electrical properties of HfO2 gate dielectrics. [ABSTRACT FROM AUTHOR]

The dependence of the performance of strained NMOSFETs on channel width was investigated. When the channel width was varied, the stress in the channel varied accordingly. This changed the electron effective mass and, consequently, the ON-state current Ion. By shrinking the channel width of a strained NMOSFET from 1 to 0.1 µm and by keeping the channel length at 55 nm, the ON-state drain current per unit channel width was enhanced by 22%. The gate leakage current was also affected by the stress in the channel, which can be explained by the increase in hole barrier height at the Si/SiO2 interface. Furthermore, when the film stress was increased by 1 GPa, the gate leakage current density Jg of a strained NMOSFET with a channel width of 0.1 µm and a length of 55 nm under a negative bias --3 V was reduced by 63 %. [ABSTRACT FROM AUTHOR]

The multicolor absorption of MOS SiGe/Si quantum-dot (QD) infrared photodetectors is demonstrated using the boron delta-doping in Si spacers. The energy-dispersive X-ray spectroscopy shows that the Ge concentration in the wetting layers is much smaller than that in QDs. Most holes stay at the ground state in QDs instead of wetting layers. The energy band structure in QDs is calculated to understand the absorption spectrum. The absorption at 3.7-6 mum is due to the intersubband transition in the SiGe QDs. The other absorption at 6-16 mu m mainly comes from the intraband transition in the boron delta-doping wells. Since the broadband spectrum covers most of the atmospheric transmission windows for infrared, the broadband detection is feasible using this device. [ABSTRACT FROM PUBLISHER]

The physical properties of HfO2 and Hf-silicate layers grown by the atomic layer chemical vapor deposition are characterized as a function of the Hf concentration and the annealing temperature. The peaks of Fourier transform infrared spectra at 960, 900, and 820 cm-1 originate from Hf-O-Si chemical bonds, revealing that a Hf-silicate interfacial layer began to form at the HfO2/SiO2 interface after postdeposition annealing process at 600°C for 1 min. Moreover, the intensity of the peak at 750 cm-1 can indicate the degree of crystallization of HfO2. The formed Hf-silicate layer between HfO2 and SiO2 is also confirmed by X-ray photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]

n-type NiO:Al thin films were deposited by RF magnetron sputtering. Their optoelectronic properties versus Al target power was investigated. The results show that with increasing Al target power, the conduction type of NiO films changes from p-type to n-type. The variation of the film’s electrical and optical properties depends on Al amount in the film. When Al target power is relatively low, Al3+ cations tend to enter nickel vacancy sites, which makes the lattice structure of NiO more complete. This improves the carrier mobility and film’s transmittance. However, when Al target power exceeds 40 W, Al atoms begin to enter into interstitial sites and form an Al cluster in the NiO film. This behavior is beneficial for improving the film’s n-type conductivity but degrades the film’s transmittance. Finally, Al/(p-type NiO)/(n-type NiO:Al)/ITO homojunctions were fabricated. Their performance was compared with Al/(p-type NiO)/ITO heterojunctions without an n-type NiO layer. Thanks to the better interface quality between the two NiO layers, the homojunctions present better performance. [ABSTRACT FROM AUTHOR]

The concept of ferroelectric (FE) negative capacitance (NC) may be a turning point in overcoming the physical limitations imposed by the Boltzmann tyranny to realize next-generation state-of-the-art devices. Both the body factor (m-factor) and the transport mechanism (n-factor) are simultaneously improved by integrating an NC with a tunnel FET (TFET). The modeling approach is discussed in this study as well as the NC physics. By optimizing the thicknesses of FE, semiconductor, and interfacial layers, the capacitance of the FE layers is modulated to match that of a MOS resulting in the smallest subthreshold swing that is also hysteresis-free. An ultrathin-body double gate tunnel FET (UTB-DG-TFET) exhibits a steep slope (a subthreshold swing below 10 mV/dec over more than 4 orders of magnitude) for low-power applications (<0.2 V switching voltage) to realize next-generation state-of-the-art devices. [ABSTRACT FROM AUTHOR]