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Summary of Jr-Tai Chen's activities


My work mainly focuses on metal-organic chemical vapor deposition (MOCVD) growth of advanced GaN-based high electron mobility transistor (HEMT) structures on SiC and GaN substrates, followed by a variety of characterization methods listed below to understand and optimize the material properties. 

  • Structural properties: Optical Microscopy, Atomic Force Microscopy, Optical Thickness Mapping, X-Ray Diffraction. 
  • Electrical properties: Capacitance-Voltage measurement, Contact-less Sheet Resistance Measurement, Contact-less Hall Mobility Measurement.
  • Thermal properties: Transient Thermal Reflectance, and Micro-Raman Spectroscopy (Collaboration with Bristol University, UK)
  • Impurity incorporations: Secondary Ion Mass Spectroscopy (done in EAG Lab)
  • Device processing: Collaboration with Chalmers University of Technology, Sweden, and United Monolithic Semiconductors, Germany.

Recent research topics related to HEMT structures

  • Reduction of thermal boundary resistance of the GaN/SiC interface 
  • Optimization of carbon incorporation and its profile in the buffer layer (GaN) to reduce the trapping effect and increase the buffer resistance
  • Development of epitaxial growth of normally-off with a p-GaN cap layer
  • Growth on true bulk GaN substrate
A wafer of HEMT structures grown at LiU and processed at Chalmers. Courtesy of Dr. Niklas Rorsman, Chalmers, Sweden.

Selected publications & conference contributions

  • Impact of residual carbon on two-dimensional electron gas properties in AlGaN/GaN heterostructure
    J. T. Chen, U. Forsberg, and E. Janzén
    Applied Physics Letters 102, 193506 (2013)
  • Temperature dependent effective mass in AlGaN/GaN high electron mobility transistor structures
    T. Hofmann, P. Kühne, S. Schöche, J. T. Chen, U. Forsberg, E. Janzén, N. B. Sedrine, C. M Herzinger, J. A Woollam, M. Schubert and V. Darakchieva
    Applied Physics Letters 101, 192102 (2012)
  • Hot-Wall MOCVD grown high-quality GaN HEMT structure: Bottom-to-top optimization
    Poster presentation at the 10th International Conference on Nitrides Semiconductors (2013)
  • Growth temperature effect on two-dimentional electron gas properties in AlGaN/GaN heterostructure
    Poster presentation at the 4th International Symposium on Growth of III Nitrides (2012)
  • High quality of AlGaN/GaN HEMTs structure grown on European-source 6H- SiC substrates
    Talk at the 5th ITP International Symposium (2012)
  • High Mobility InAlN-barrier HEMTs grown by hot-wall MOCVD
    Poster presentation at the 3th International Symposium on Growth of III Nitrides (2011)


  • TFFM08 Experimental physics (6 ECTS), lab assistant responsible for XRD and Holography
Jr-Tai Chen


Host: Erik Janzén


E-mail: jrche@ifm.liu.se
Phone: +46 (0)13 28 26 99

Room K208 (Physics Building)

Semiconductor Materials, IFM
Linköping University
Linköping, Sweden


Erik Janzén, main
Urban Forsbergco



Responsible for this page: Fredrik Karlsson
Last updated: 02/11/14