Search

In0.17Al0.83N/GaN high‐electron‐mobility transistor (HEMT) using GaN‐on‐Insulator (GaNOI) technology via 200 mm wafer bonding technique is developed with good DC and RF performance and high fT/fmax. Measurements obtained from X‐Ray diffraction and micro‐Raman spectroscopy have demonstrated a 5% reduction in "a lattice strain," which results in the improvement of the sheet resistance (Rsh) from 301 to 284 Ω □−1. A 120 nm gate‐length device achieves a peak fT up to 96 GHz which yields a fT × Lg value of 11.5 GHz μm, which compares favorably with reported GaN‐based HEMTs on Si. These results demonstrate that GaNOI HEMT on Si is an attractive candidate for future mm‐wave applications. The implementation of GaNOI technology facilitates the integration of GaN devices into a chip alongside complementary metal–oxide–semiconductor technology that opens up the potential for integrated high‐power and RF applications, enabling more compact and efficient systems. [ABSTRACT FROM AUTHOR]

This work investigates the off-state leakage characteristics of AlN/GaN/AlGaN high electron mobility transistors (HEMTs) on Si substrate with varying mesa depths and uncovers the existence of a parasitic channel associated with the AlGaN back barrier. Significant differences in off-state leakage up to three orders of magnitude were observed between devices fabricated using different mesa depths. The electrical properties of AlN/GaN/AlGaN HEMTs were measured, and it was found that there is a N-type parasitic channel in the unintentionally doped AlGaN back-barrier. Analysis of the isolation test structure, which retains this parasitic channel, reveals a buffer leakage of 12.8 mA/mm and a sheet resistance of 7739.1 Ω/sq, as a result of the parasitic channel. The depletion electric field strength of the parasitic channel is 3.2 × 105 V/cm. Temperature-dependent I–V curves obtained from the isolation area affirm that the primary leakage mechanism is two-dimensional variable range hopping along the sidewall. As the isolation distance extends from 3 to 5 μm, the slope of the fitting line decreases from −53.14 to −126.11 due to increased resistance. [ABSTRACT FROM AUTHOR]

Purpose: Developmental anomalies of the Atlas vertebrae are often encountered during the investigation of cervical pain. So this study was designed to find the variation of the Atlas vertebra. Methods: A total of hundred dried Atlas vertebrae of unknown age and sex of the Northern population of India were examined to find the congenital defect of the Atlas vertebra in the Department of Anatomy. Results: The presence of incomplete foramen transversarium was found in 6 % vertebrae. The Retroarticular canal was found in 9 %vertebrae. The bony spur originated from the posterior aspect of the superior articular facet was seen in 5% vertebrae. No anomaly was found in the anterior arch whereas aplasia of the posterior arch was found in 3% vertebrae. Conclusion: The first cervical vertebra often presence the development anomaly. Such developmental abnormalities in different parts of Atlas vertebrae produce various clinical symptoms. The knowledge of such variation helps clinicians to distinguish it from the fracture and to find an accurate clinical diagnosis. [ABSTRACT FROM AUTHOR]

This work investigates the multi-energy ultra-heavy 131Xe+ ion implantation for the realization of planar AlGaN/GaN high electron mobility transistors (HEMTs) on Si. The 131Xe+ implant-isolation in AlGaN/GaN HEMT structure exhibited an order of magnitude lower buffer leakage current as well as an order of magnitude higher ON/OFF current ratio ( Ion/Ioff) and sheet resistance ( Rsh) when compared with conventional mesa-isolation process. The isolated region by 131Xe+ implantation demonstrated good thermal stability in the isochronal annealing up to 800 ºC. A stable buffer breakdown voltage with and without Si3N4 passivation were observed using implant-isolation. The AlGaN/GaN HEMTs isolated by 131Xe+ implantation exhibited good pinch-off characteristics with one order of magnitude lower OFF-state source-drain leakage and reverse gate leakage current and improved OFF-state breakdown voltages by ∼106-128 V as compared to the mesa-isolated devices. An activation energy of 0.513 eV was extracted, which denotes the energy level of lattice damage by 131Xe+ ions. These results indicate that multi-energy implant-isolation by ultra-heavy 131Xe+ ions is promising for the fabrication of planar AlGaN/GaN HEMTs with improved device characteristics. [ABSTRACT FROM AUTHOR]

A low voltage (−20 V) operating high-energy (5.48 MeV) α-particle detector with a high charge collection efficiency (CCE) of approximately 65% was observed from the compensated (7.7 × 1014 /cm3) metalorganic vapor phase epitaxy (MOVPE) grown 15 µm thick drift layer gallium nitride (GaN) Schottky diodes on free-standing n+-GaN substrate. The observed CCE was 30% higher than the bulk GaN (400 µm)-based Schottky barrier diodes (SBD) at −20 V. This is the first report of α–particle detection at 5.48 MeV with a high CCE at −20 V operation. In addition, the detectors also exhibited a three-times smaller variation in CCE (0.12 %/V) with a change in bias conditions from −120 V to −20 V. The dramatic reduction in CCE variation with voltage and improved CCE was a result of the reduced charge carrier density (CCD) due to the compensation by Mg in the grown drift layer (DL), which resulted in the increased depletion width (DW) of the fabricated GaN SBDs. The SBDs also reached a CCE of approximately 96.7% at −300 V. [ABSTRACT FROM AUTHOR]