A5074735727- GaN-based semiconductor devices and materials
- Semiconductor materials and devices
- Ga2O3 and related materials
- Semiconductor Quantum Structures and Devices
- Radio Frequency Integrated Circuit Design
- Photonic and Optical Devices
- Semiconductor Lasers and Optical Devices
- Integrated Circuits and Semiconductor Failure Analysis
- Thin-Film Transistor Technologies
- Laser Material Processing Techniques
University of Padua
2023-2024
Application of gallium nitride high-electron-mobility transistors (GaN HEMTs) to millimeter-wave power amplifiers requires gate length scaling below 150 nm: in order control short-channel effects, the gate-to-channel distance must be decreased, and device epitaxial structure has completely redesigned. A high 2-D electron gas (2DEG) carrier density can preserved even with a very thin top barrier layer by substituting AlGaN AlN, InAl(Ga)N, or ScAlN. Moreover, prevent interaction hot electrons...
For the first time we investigate optical degradation of vertical-cavity silicon-integrated lasers VCSILs) designed for operation at 845 nm in photonic integrated circuits (PICs). The study is based on combined electro-optical characterization VCSIL, submitted to constant-current stress tests different current levels. original results obtained within manuscript indicate that related diffusion impurities. Remarkably, depending region through which these impurities are migrating, process...
Reliability and failure mechanism of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{0.25 \ \mu }\mathbf{m} \mathbf{AlGaN}/\mathbf{GaN}$</tex> HEMTs under thermal storage tests high temperature operating life (HTOL) have been evaluated. Results show that, during tests, Schottky metal interdiffusion gate sinking took place, possibly accompanied by thermo-mechanical degradation, with an activation energy 1.8 eVe Failure modes...
DC characteristics of AlGaN/GaN HEMTs with different thickness values the undoped GaN channel layer were compared. An abnormal transconductance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${g}_{m}{)}$ </tex-math></inline-formula> overshoot accompanied by a negative threshold voltage notation="LaTeX">${V}_{\text {TH}}{)}$ shift was observed during notation="LaTeX">${I}_{\text {DS}}$ – {GS}}$ sweep in...
A full characterization of deep level effects in N-polar GaN-based HEMTs has been carried out by means Drain Current Transient Spectroscopy (DCTS). The effect ohmic contacts (alloyed or regrown), composition AlGaN cap layer, and the quality epitaxial layers have studied. We show that occurrence an "antidispersion" effect, i.e. a transient increase I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</inf> during pulsed measurements, is due to...
Laser diodes are of paramount importance for on-chip telecommunications applications, and a wide range sensing devices that require near-infrared sources. In this work, the under test vertical-cavity silicon-integrated lasers (VCSILs) designed operation at 845 nm in photonic integrated circuits (PICs). We focus on analysis degradation optical performance during aging. To investigate reliability devices, we carried out several stress tests constant current, ranging from 3.5 mA to 4.5...
Optical and electrical degradation of novel micro-transfer-printed VCSILs is investigated. Modeling experimental data suggests that the main mechanism represented by relocation impurities, originating from p-side, toward active region.
The kink effect in field-effect transistors (FETs) consists a sudden increase drain current, I D , during voltage sweep and leading to higher saturation value.We report new experimental data concerning the dynamic behavior of "kink" AlGaN/GaN HEMTs correlate them with deep levels.The results demonstrate role Poole-Frenkel determining occurrence identify conditions that make it observable.