Solid-state Electronics最新文献

We present a versatile compact model for resistive random-access memory (RRAM) that can model different types of RRAM devices such as oxide-RRAM (OxRAM) and conducting-bridge-RRAM (CBRAM). The model unifies the switching mechanisms of these RRAMs into a single framework. We showcase the model’s accuracy in reproducing published experimental device DC and transient characteristics of various RRAM structures. We also demonstrate the model’s efficacy in capturing RRAM variability and conducting 1T1R circuit simulations.

A normally-off GaN MOSFET is successfully fabricated by using the selective regrowth technique (SRT) with regrown AlGaN layer on source/drain (S/D) region. The GaN MOSFET with regrown AlGaN layer and L_g of 10 μm shows enhanced electrical performance such as maximum drain current (I_D,max) of 57 mA/mm, maximum transconductance (g_m,max) of 11 mS/mm, and field-effect mobility (μ_FE) of 59 cm²/V·s, respectively, compared to the GaN MOSFET with n⁺-GaN selective regrowth in S/D region. This is because of the high 2DEG density formed by AlGaN/GaN heterojunction in S/D region. Moreover, to accommodate the poor structural quality of the narrow region regrowth of AlGaN layer on the S/D region, wide regrown AlGaN layer is applied to the GaN MOSFET. Especially, the off-state breakdown voltage improves from 25 V to 192 V with the improved structural quality of wide regrown AlGaN layer and optimized structure and the application of the 70-nm thick SiO₂ passivation. These result shows that GaN MOSFET with wide regrown AlGaN layer on S/D region is beneficial to achieving high-quality and uniform normally-off GaN MOSFETs with excellent electrical performance.

This paper presents a hybrid model for TiO₂-based memristors, integrating the dopant drift mechanism with the Schottky barrier theory. We introduce the movement of oxygen vacancies as a dynamic variable to modulate changes in memristors. Furthermore, the variation of the dominate mechanism of the TiO₂ memristors under different operating conditions is studied, which is related to the position of the internal oxygen vacancy. The proposed model accurately captures the rectification linearity, and effectively elucidates the dominant current mechanisms manifested in six distinct regions of the I-V curves. Our model exhibits better predication with reduced errors when applied to Pt/TiO₂/Pt memristors. The proposed model can well describe the dual-mechanism memristor phenomenon, and provides a reference for the subsequent study of multi-mechanism behavior in memristors.

The large numbers of high-energy carriers that occur in semiconductor devices under semi-on state conditions can cause significant device degradation. The effects of different stresses on the electrical and trapping characteristics of GaN-based high-electron-mobility transistors (HEMTs) are investigated. Test results for GaN HEMTs under semi-on state conditions show that the electrical characteristics of these devices degrade to a certain extent after they are subjected to electrical pulse stress cycles with different drain voltage, frequencies, and duty cycles; a degree of degradation also occurs in the electrical characteristics of the devices when they are subjected to direct current electrical stresses. After electrical stress is applied, the absolute amplitude of the traps in the device increases, thus indicating an increase in the trap density. The results show that voltage is the main driver for device damage, with the current playing an accelerating role through its effects on device temperature or by supplying hot electrons; therefore, the drain voltage has the most significant effect on device degradation, which is mainly due to channel high-energy hot electron injection.

Significant discrepancies were found between experimental results and the results calculated by the conventional physics-based model for the cutoff frequency and some equivalent circuit parameters of double heterojunction bipolar transistors (DHBT). In order to accurately evaluate the primary quantitative performance of DHBT, a comprehensive physics-based model was developed and validated by comparing experimental data from three research institutions. The proposed physics-based model combines the equivalent circuit of the T-topology and hybrid-π topology, and includes modification formulas for estimating the intrinsic dynamic resistance of the base–collector and base-emitter junctions, as well as the cutoff frequency, the hybrid-π input capacitance, and the gain.

In this research, we reported that manganese and copper atoms were embedded in silicon-carbon films to fabricate impedance organic vapor sensors. Gas sensitive layers were formed using electrochemical deposition of 9:1 CH₃OH/HMDS solutions, followed by thermal annealing at 500 °C for 2 h. Silicon-carbon films contain 4H-SiC, 15R-SiC and 6H-SiC polytypes, as well as amorphous diamond phases. Mott-Schottky plots were used to evaluate the silicon-carbon films conductivity type, flat band potential and carrying density. Sensor operations were examined at ambient temperature and up to 80 % relative humidity to assess their functionality. The silicon-carbon films impedance sensors detected 6–37 ppb toluene vapor. The manganese and copper embedded in silicon-carbon films detected 5–52 ppb isopropanol vapor and remained unchanged in humidity range (40–65 %). However, at humidity level up to 80 %, the sensing response range decreases by ≈1.5–2 times, with isopropanol significantly contributing to the response.

A unified and complete capacitance model of metal oxide thin-film transistors (MO TFTs) based on three-terminal charges is proposed in this paper. The analytical expression of the three-terminal charges is obtained with the effective charge density approach and the Ward-Dutton charge partitioning approach. By considering the non-reciprocal capacitance between any two terminals, the complete capacitance model of the MO TFTs is proposed with an accurate description. The proposed model has a uniform and analytical capacitance expression over the full working regions with a specific physical meaning based on the surface potential solution. Furthermore, the sufficient capacitance experimental data of the fabricated IZO-TFT are presented to verify the proposed model. It is shown that there is a good agreement between the experimental data and the proposed model in a wide range of working regions.

A novel approach to determine the source series resistance for InP HEMT device, which combines the DC characteristics measurement and S-parameters measurement under normal bias condition is developed in this paper. Three HEMT devices with different gatewidth have been used to verify the validity of the method, and good agreement is obtained between modeled and measured S-parameters and noise parameters.

This work presents the fabrication and electrical characterization of the Ion Sensitive Field Effect Transistor (ISFET) exposed to potassium chloride (KCl) solutions. The focus of the study is to compare two measurements methods and verify the effects of these methods in the device threshold voltage (V_TH) sensitivity to the different KCl concentrations. First, a reference electrode (a platinum needle) is placed in the sample solution over the gate area of the device, demonstrating that the threshold voltage decreases with the increase of the KCl concentration. The method shows a sensitivity of 10.44 mV/mM for the low KCl concentration range (0 to 10 mM) and 0.5 mV/mM for the higher KCl concentration range (10 to 100 mM). The second method involves inserting a second platinum electrode into the solution on the field oxide. This method proposes the KCl electrolysis to increase the selectivity for potassium ions. The result allows the next steps for potassium sensing biosensor application with selective membranes.