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Research

                 As a commercially immature technology, GaN-based power transistors are plagued by electrical performance degradation when stressed.  An irreversible phenomenon known as current collapse is observed whenever an electric field between drain and gate exceeds a critical value.  It is suspected that trapped charge is generated, which leads to virtual gating of the device.  The resulting current/voltage characteristics are undesirably shifted.

           My research project aims to investigate the use of a passivation layer to help alleviate problems with current collapse in AlGaN/GaN HEMT’s.  By examining interfacial chemistry and electrical data, my goal is to develop a correlation to better explain the current collapse phenomenon.  With a better understanding of the HEMT structure, process development could lead to the fabrication of commercially viable devices.

                 For as long as I can remember I have been fascinated with computers.  Growing up with Moore’s law kept me endlessly speculating how fast processors would go or how large hard disks would be.  It was a natural choice to continue studying microelectronics at Penn State in undergraduate Electrical Engineering.  After some time in the Engineering Science and Mechanics graduate program, I switched to Materials Science and Engineering to pursue a Ph.D. focusing on the growth and fabrication of AlGaN/GaN high electron mobility transistors (HEMT’s).

Dave at Age 3, using an Apple IIe (1984)