Former Research

LEDs for automotive applications: From indicators to illuminators

Although LED headlamps have been made and shown in concept cars by a few automotive manufacturers, many issues remained to be resolved for LED lamps to replace high intensity discharge (HID) lamps.  In this program, we propose to investigate some of these issues with possible resolutions.

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III-nitride growth on silicon by MOCVD for electron device applications

Successful deployment of III-nitride power amplifiers on Si substrates will have tremendous impact in the future capability of base stations for wireless communications. In this project, we aim to develop novel techniques of growing III-nitride epitaxy on Si, specifically for electronic device applications. Here, we propose to address some of the outstanding problems and attempt to carry out uniform and patterned growth on Si.

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Reliability study on GaN based transistors for communication applications

In this project, we will study the reliability and stability of the GaN HEMT (High Electron Moility Transistor) and seek to eliminate the obstacles to commercialize this device. GaN epitaxial material will be grown, and devices will be fabricated.  Systematic realiability tests and analysis will be performed. Afterwards, an optimized material structure and a reliable device will be prepared for veritifcation. The success of this work would greatly benefit the communications field and have great potential for business.

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Metamorphic heterostructure bipolar transistors

The purpose of this project is to investigate the feasibility of depositing highfrequency Heterojunction Bipolar Transistor (HBT) structures on GaAs substrates by Metalorganic Chemical Vapor Deposition (MOCVD), in an attempt to address some of the issues that would help advance high frequency and high-speed devices for low cost manufacturability.

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Enhancement-mode AlGaN/GaN HEMTs and Their Circuit

(PI, Professor Kevin J Chen)

Recently, we have developed a novel approach of fabricating high performance enhancement-mode AlGaN/GaN HEMTs using fluoridebased plasma treatment technique. Focusing on in-depth understanding and exploration of circuit applications of this technology, we propose to carry out a comprehensive investigation on a number of key issues.

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High-Linearity III-Nitride Composite-Channel High Electron Mobility Transistors (HEMT) for RF/Microwave Applications

(PI, Professor Kevin J Chen)

Because of the importance of device linearity on the performance of modern wireless systems, the intensity in characterizing and improving the AlGaN/GaN HEMTs’ linearity is picking up. Our thrust in this project is to explore new HEMT structures through channel engineering that could lead to enhanced linearity. Focusing on a novel composite-channel HEMT which we recently demonstrated, we propose to carry out a comprehensive investigation on a number of key issues.

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Development of Deep Submicron Gallium Nitride Heterostructure Field-Effect Transistors for High-Power Low-Noise for RF/Microwave Applications

(PI, Professor Kevin J Chen)

GaN-based high electron mobility transistors (HFET) promise to have major impact on electronics, making possible the creation of transistors with 10-20 times better power handling than the current Si and GaAs devices can provide. These devices also possess low microwave noise, owing to the tightly confined two-dimensional electron gas and the associated high charge density.  Taking advantage of the low noise and the inherent large breakdown field in the wideband GaN-based materials, high-performance RF front-end circuits can be realized with no need for protection circuitry, and therefore greatly simplifying system designs. The low noise behavior is also critical to achieving low phase noise in GaN-based voltage-controlled oscillators. In this project, the teams from Hong Kong University of Science and Technology (HKUST) and the Institute of Microelectronics, Chinese Academy of Science (IMECAS) propose to conduct joint research on the development of deep submicron AlGaN/GaN HFET for high-power and low-noise RF/microwave applications. Our research teams are formed with experts in material growth, device fabrication and high frequency characterization. The project is divided into three interlinked thrusts: 1) Material growth and characterization; 2) Device structure design and processing techniques of deep submicron (e.g. 0.15 micron gate length) gates; and 3) RF/microwave characterization.