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This study presents a β-Ga2O3 Schottky barrier diode (SBD) with a Mg current blocking layer (Mg-CBL) fabricated via the Mg-doped spin-on-glass (Mg-SOG) technique, affording a surface roughness damage-free thermal doping process. The proposed technique improves the breakdown voltage (BV) of the β-Ga2O3 SBD from 580 to 2200 V and marginally increases the specific on-resistance from 4.0 to 4.8 mΩ cm2, yielding a notable power figure of merit exceeding 1 GW/cm2. The Mg-CBL effectively captures the electrons and mitigates the electric field, leading to a significant increase in BV and slight decrease in the forward current loss. The temperature-dependent I–V curves reveal that the reverse saturation current decreases owing to the physical mechanism of the Mg-CBL structure. Moreover, the Gaussian distribution model is applied to correct the Schottky barrier inhomogeneity stemming from the Mg-CBL. The results illustrate the promising potential of the Mg-CBL fabricated via the Mg-SOG technique for yielding high-performance β-Ga2O3 SBDs. [ABSTRACT FROM AUTHOR]

In this work, the DC performance and RF characteristics of GaN-based high-electron-mobility transistors (HEMTs) using the SiNx stress-engineered technique were systematically investigated. It was observed that a significant reduction in the peak electric field and an increase in the effective barrier thickness in the devices with compressive SiNx passivation contributed to the suppression of Fowler–Nordheim (FN) tunneling. As a result, the gate leakage decreased by more than an order of magnitude, and the breakdown voltage (BV) increased from 44 V to 84 V. Moreover, benefiting from enhanced gate control capability, the devices with compressive stress SiNx passivation showed improved peak transconductance from 315 mS/mm to 366 mS/mm, along with a higher cutoff frequency (ft) and maximum oscillation frequency (fmax) of 21.15 GHz and 35.66 GHz, respectively. Due to its enhanced frequency performance and improved pinch-off characteristics, the power performance of the devices with compressive stress SiNx passivation was markedly superior to that of the devices with stress-free SiNx passivation. These results confirm the substantial potential of the SiNx stress-engineered technique for high-frequency and high-output power applications, which are crucial for future communication systems. [ABSTRACT FROM AUTHOR]

Although the relationship between vaginal microorganisms and fertility has been well established, only few studies have investigated vaginal microorganisms in women undergoing in vitro fertilization (IVF). Our aim was to study the differences in vaginal microbiota between infertile women with repeated implantation failure (RIF) and those who achieved clinical pregnancy in their first frozen embryo transfer cycle. We compared the vaginal microbiota of patients with a history of RIF (n = 37) with that of the control group (n = 43). Following DNA extraction, metagenomic sequencing was employed for the analysis of alpha and beta diversities, distinctions in bacterial species, and the functional annotation of microbial genes. Furthermore, disparities between the two groups were revealed. Alpha diversity analysis revealed that the Shannon index was higher in the RIF group (P < 0.05). There were differences in the beta diversity between groups (P = 0.16). At the bacterial family level, the relative abundance of Actinomycetaceae (P = 0.013) and Ruminococcaceae (P = 0.013) were significantly higher in the RIF group. At the genus level, the abundances of Actinomyces (P = 0.028) and Subdoligranulum (P = 0.013) were significantly higher in the RIF group. At the species level, the abundances of Prevotella timonensis (P = 0.028), Lactobacillus jensenii (P = 0.049), and Subdoligranulum (P = 0.013) were significantly higher in the RIF group. Significant differences in family, genus, species, alpha and beta diversity were observed in the vaginal microbiota between groups. Notably, among these findings, the Subdoligranulum genus emerged as the most prominent correlating factor. [ABSTRACT FROM AUTHOR]

This work demonstrates a high-performance monolithically integrated GaN inverters platform, which incorporates enhancement-mode (E-mode) and depletion-mode (D-mode) GaN high-electron-mobility transistors (HEMTs) simultaneously using an Al:HfOx-based charge trapping layer. The developed E-mode HEMT exhibits a positive threshold voltage of 2.6 V, a high ON–OFF current ratio of 1.9 × 108, a current density of 376 mA/mm, and an ON-resistance of 15.31 Ω·mm. Moreover, the direct-coupled field-effect-transistor logic (DCFL) GaN inverter was characterized with and without D-mode device threshold voltage (VTH) modulation, demonstrating improved output swing and switching threshold shift by proposed VTH modulation. The optimized DCFL GaN inverter manifests a switching threshold of 2.34 V, a logic voltage output swing of 4.98 V, and substantial logic-low and logic-high noise margins of 2.16 and 2.49 V, respectively, at a supply voltage of 5 V. These results present a promising approach toward realizing monolithically integrated GaN logic circuits for power IC applications. [ABSTRACT FROM AUTHOR]

In this work, high threshold voltage and breakdown voltage E-mode GaN HEMTs using an Al:HfOx-based charge trapping layer (CTL) are presented. The developed GaN HEMTs exhibit a wide threshold modulation range of ΔVTH ∼ 17.8 V, which enables the achievement of enhancement-mode (E-mode) operation after initialization process owing to the high charge storage capacity of the Al:HfOx layer. The E-mode GaN HEMTs exhibit a high positive VTH of 8.4 V, a high IDS,max of 466 mA/mm, a low RON of 10.49 Ω mm, and a high on/off ratio of ∼109. Moreover, the off-state breakdown voltage reaches up to 1100 V, which is primarily attributed to in situ O3 pretreatment effectively suppressing and blocking leakage current. Furthermore, thanks to the VTH of GaN HEMTs being tunable by initialization voltage using the proposed CTL scheme, we prove that the direct-coupled FET logic-integrated GaN inverters can operate under a variety of conditions (β = 10–40 and VDD = 3–15 V) with commendable output swing and noise margins. These results present a promising approach toward realizing the monolithic integration of GaN devices for power IC applications. [ABSTRACT FROM AUTHOR]

In this study, nine component points were designed based on a CaO‐B2O3‐SiO2 (CBS) glass system with a high boron content, and CBS glass/Al2O3 composites were developed for low‐temperature co‐fired ceramic (LTCC) applications. Furthermore, the densification process, phase compositions, microstructures, and properties were investigated. The results indicated that the softening of glass and interfacial reaction between the glass and Al2O3 were the two most important factors affecting LTCC's densification process. The real‐time shrinkage rate of LTCC during sintering was simulated using the thermal shrinkage curve and combined with DTA and X‐ray diffraction. It was proven that the formation of the CaAl2(BO3)O phase contributed to the reduction in glass viscosity and promoted the formation of a dense structure. The LTCC composite with 30 vol% glass sintered at 850°C exhibited a coefficient of thermal expansion of 4.55–6.35 ppm/◦C, εr of 3.5–5.0, and a minimum tan δ of 0.0018 at 15 GHz. Therefore, these properties make the CBS–LTCC more suitable for high‐frequency applications. [ABSTRACT FROM AUTHOR]