Reduction of impact ionization in GaAs-based planar gunn diodes by anode contact design

Montes, M., Dunn, G., Stephen, A., Khalid, A. , Li, C. , Cumming, D. , Oxley, C.H., Hopper, R.H. and Kuball, M. (2012) Reduction of impact ionization in GaAs-based planar gunn diodes by anode contact design. IEEE Transactions on Electron Devices, 59(3), pp. 654-660. (doi: 10.1109/TED.2011.2177094)

Full text not currently available from Enlighten.

Publisher's URL:


Impact ionization in GaAs-based planarGunn diodes is studied through electroluminescence (EL) analysis with the aim of reducing its magnitude by means of contact design and shaping, and thus enhance device performance and reliability. Designs in which the diode ohmic anode has an overhanging Schottky extension (composite anode contact) are shown to result in a significantly reduced amount of impact ionization, as compared with a simple ohmic contact design. The EL results are consistent with Monte Carlo simulations, which show a reduced impact ionization in composite anode contact devices due to a reduced electron density beneath the anode Schottky extension that, on the one hand, weakens the Gunn domain electric field and softens its variations near the anode edge, and, on the other hand, reduces the number of electrons capable of generating holes by impact ionization. A comparison between standard and composite anode contact approaches in terms of radio-frequency operation of the devices is made showing oscillations up to 109 GHz with an output power of -5 dBm in devices featuring the composite anode contact and no oscillations from all-ohmic contact devices. The findings reported in this paper may be useful not only for the design and the fabrication of planar Gunn diodes but also for other devices such as high-electron-mobility transistors where impact ionization can result in reliability limitations.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Li, Dr Chong and Cumming, Professor David and Khalid, Dr Ata-Ul-Habib
Authors: Montes, M., Dunn, G., Stephen, A., Khalid, A., Li, C., Cumming, D., Oxley, C.H., Hopper, R.H., and Kuball, M.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:IEEE Transactions on Electron Devices
Publisher:Institute of Electrical and Electronics Engineers

University Staff: Request a correction | Enlighten Editors: Update this record

Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
497131Novel Thermal Management Concepts: High Power High Frequency Planar Gunn DiodeDavid CummingEngineering & Physical Sciences Research Council (EPSRC)EP/H011862/1Electronic and Nanoscale Engineering