IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Semiconductors Monday Sessions
       Session SC-MoA

Invited Paper SC-MoA8
Models, Concepts and Realizations of Pyroelectronic Heterostructure Devices

Monday, October 29, 2001, 4:20 pm, Room 124

Session: GaN Surfaces, Interfaces, and Devices
Presenter: P. Vogl, Technische Universitaet Muenchen, Germany
Authors: P. Vogl, Technische Universitaet Muenchen, Germany
G. Zandler, Technische Universitaet Muenchen, Germany
S. Hackenbuchner, Technische Universitaet Muenchen, Germany
J.A. Majewski, Technische Universitaet Muenchen, Germany
O. Ambacher, Technische Universitaet Muenchen, Germany
K. Chu, Cornell University
V. Tilak, Cornell University
R. Dimitrov, Cornell University
L.F. Eastman, Cornell University
Correspondent: Click to Email
High field transport in semiconductors that possess high internal spontaneous electric fields opens up a new field of "pyroelectronics". The pyroelectric character of group-III-nitrides with wurtzite crystal structure yields a novel degree of freedom in designing and tayloring devices for modern microelectronic applications. We present both theoretical and experimental studies of III-nitride based high electron mobility field effects transistors (HEMT´s) that demonstrate these devices to be optimally suited for high power and high frequency transistors as well as microwave amplifiers. On the theory side, we have employed first principles calculations to determine spontaneous and piezoelectric polarization charges at interfaces and surfaces of GaN based heterostructures and superlattices. Based on this calculated set of electronic structure data, we have performed extensive high field transport simulations for submicron HEMT devices. In addition, we show how the built-in electric fields can be utilized to produce high hole densities as a function of gate voltage in these devices. Experimentally, undoped and pyroelectric AlGaN/GaN HEMT´s have been processed on c-Al@sub 2@O@sub 3@, Si(111) and 6H-SiC substrates that show excellent device characteristics. With gate length down to 150 nm, we have reached an electron transit velocity and intrinsic transit time frequency of 1.3x10@super 7@ cm/s and 106 GHz, respectively, at room temperature. Experimental results for the first microwave amplifier build by a combination of 4x4 AlGaN/GaN HEMTs will be presented.