arXiv subjects

Ting-Chang Chang

Publications and source records attributed to Ting-Chang Chang.

6 recordsLinked to original sources

arXiv2024

Impacts of Backside Insulation on the Dynamic On-Resistance of Lateral p-GaN HEMTs-on-Si

We examined the effect of backside insulation on the dynamic on-resistance of lateral p-GaN HEMTs. To gain a comprehensive understanding of the dynamic onresistance difference between substrate grounded and substrate floating p-GaN HEMTs, we conducted in-circuit double pulse testing and long-term direct current (DC) bias stress. We have realized that while backside insulation can enhance the breakdown voltage of lateral p-GaN HEMTs, it also comes with a tradeoff in device reliability. Results through Sentaurus TCAD simulation suggest that the use of backside insulation in devices gradually disperses potential to the buffer barrier. As a result, the potential barrier at the buffer edge of the 2DEG channel decreases significantly, leading to considerable electron trappings at buffer traps. This breakdown voltage and reliability tradeoff also applies to HEMT technologies using insulating substrates.

physics.app-ph↗

arXiv2021

Dynamic Behaviors and Training Effects in TiN/Ti/HfO$_x$/TiN Nanolayered Memristors with Controllable Quantized Conductance States: Implications for Quantum and Neuromorphic Computing Devices

Controllable quantized conductance states of TiN/Ti/HfO$_x$/TiN memristors are realized with great precision through a pulse-mode reset procedure, assisted with analytical differentiation of the condition of the set procedure, which involves critical monitoring of the measured bias voltage. An intriguing training effect that leads to faster switching of the states is also observed during the operation. Detailed analyses on the low- and high-resistance states under different compliance currents reveal a complete picture of the structural evolution and dynamic behaviors of the conductive filament in the HfO$_x$ layer. This study provides a closer inspection on the quantum-level manipulation of nanoscale atomic configurations in the memristors, which helps to develop essential knowledge about the design and fabrication of the future memristor-based quantum devices and neuromorphic computing devices.

cond-mat.mes-hall↗

arXiv2017

Weak Localization and Weak Antilocalization in Double-Gate a-InGaZnO Thin-Film Transistors

We demonstrate manipulation of quantum interference by controlling the competitions between weak localization (WL) and weak antilocalization (WAL) via variation of the gate voltages of double- gate amorphous InGaZnO thin-film transistors. Our study unveils the full profile of an intriguing universal dependence of the respective WL and WAL contributions on the channel conductivity. This universality is discovered to be robust against interface disorder.

cond-mat.mes-hall↗

arXiv2017

Universal dependence on the channel conductivity of the competing weak localization and antilocalization in amorphous InGaZnO$_4$ thin-film transistors

We investigate the gate-voltage dependence of the magnetoconductivity of several amorphous InGaZnO$_4$ (a-IGZO) thin-film transistors (TFTs). The magnetoconductivity exhibits gate-voltage- controlled competitions between weak localization (WL) and weak antilocalization (WAL), and the respective weights of WL and WAL contributions demonstrate an intriguing universal dependence on the channel conductivity regardless of the difference in the electrical characteristics of the a-IGZO TFTs. Our findings help build a theoretical interpretation of the competing WL and WAL observed in the electron systems in a-IGZO TFTs.

cond-mat.mes-hall↗

arXiv2017

Competing weak localization and weak antilocalization in amorphous indium-gallium-zinc-oxide thin-film transistors

We have investigated the gate-voltage dependence and the temperature dependence of the magnetoconductivity of amorphous indium-gallium-zinc-oxide thin-film transistors. A weak-localization feature is observed at small magnetic fields on top of an overall negative magnetoconductivity at higher fields. An intriguing controllable competition between weak localization and weak antilocalization is observed by tuning the gate voltage or varying the temperature. Our findings reflect controllable quantum interference competition in the electron systems in amorphous indium-gallium-zinc-oxide thin-film transistors.

cond-mat.mes-hall↗

arXiv2017

Monolithic Integration of AlGaAs Distributed Bragg Reflectors on Virtual Ge Substrates via Aspect Ratio Trapping

High quality AlxGa1-xAs distributed Bragg reflectors (DBRs) were successfully monolithically grown on on-axis Si (100) substrates via a Ge layer formed by aspect ratio trapping (ART) technique. The GaAs/ART-Ge/Si-based DBRs have reflectivity spectra comparable to those grown on conventional bulk off-cut GaAs substrates and have smooth morphology, and good periodicity and uniformity. Anitphase domain formation is significantly reduced in GaAs on ART-Ge/Si substrates, and etch pit density of the GaAs base layer on the ART-Ge substrates ranges from 10^5 to 6 x 10^6 cm^(-2). These results paved the way for future VCSEL growth and fabrication on these ART-Ge substrates and also confirm that virtual Ge substrates via ART technique are effective Si platforms for optoelectronic integrated circuits.

cond-mat.mtrl-sci↗