Article

Oxygen Ion Implantation Isolation Planar Process for AlGaN/GaN HEMTs

Nat. Chiao Tung Univ., Hsinchu
IEEE Electron Device Letters (Impact Factor: 2.79). 07/2007; DOI: 10.1109/LED.2007.896904
Source: IEEE Xplore

ABSTRACT A multienergy oxygen ion implantation process was demonstrated to be compatible with the processing of high- power microwave AlGaN/GaN high electron mobility transistors (HEMTs). HEMTs that are isolated by this process exhibited gate-lag- and drain-lag-free operation. A maximum output power density of 5.3 W/mm at Vgs = -4 V and Vds = 50 V and a maximum power added efficiency of 51.5% at Vgs = -4 V and Vds = 30 V at 3 GHz were demonstrated on HEMTs without field plates on sapphire substrate. This isolation process results in planar HEMTs, circumventing potential problems with enhanced gate leakage due to the gate contacting the 2-D electron gas at the mesa sidewall.

2 Bookmarks
 · 
204 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: AlGaN/GaN 70-nm-gate high-electron mobility transistors (HEMTs) fabricated using either ion implantation or conventional mesa isolation are compared. Although the resulting devices display comparable dc characteristics, the isolation process influences the RF and pulsed I - V characteristics. Although others have described implant-isolated GaN HEMTs, published reports focused on limited performance metrics, such as the gate leakage current. The present multiparametric study explicitly contrasts the performance of ion-implanted devices to otherwise identical mesa-isolated deep-submicrometer high-speed AlGaN/GaN HEMTs, in terms of transistor cutoff frequencies, small-signal model parameters, microwave noise performance, gate leakage currents, and large-signal pulsed I - V characteristics. We find that implant isolation can bring compelling advantages in terms of bandwidth, microwave noise performance, and tighter parametric distributions.
    IEEE Electron Device Letters 09/2011; · 2.79 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This letter reports the fabrication of a GaN heterostructure field-effect transistor with oxide spacer placed on the mesa sidewalls. The presence of an oxide spacer effectively eliminates the gate leakage current that occurs at the channel edge, where the gate metal is in contact with the 2-D electron gas edge on the mesa sidewall. From the two-terminal gate leakage current measurements, the leakage current was found to be several nA at VG=-12 V and at VG=-450 V. The benefits of the proposed spacer scheme include the patterning of the metal electrodes by plasma etching and a lower manufacturing cost.
    IEEE Electron Device Letters 01/2013; 34(10):1232-1234. · 2.79 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This letter reports a comparison of AlGaN/GaN high-electron-mobility transistors (HEMTs) fabricated on the same wafer using mesa etch or ion implantation as the isolation technology. The devices fabricated with ion implantation show similar DC performance (i.e., current density and on-resistance) to the devices with mesa isolation but have a higher breakdown voltage for the same gate-to-drain distance. AlGaN/GaN HEMTs with a breakdown voltage of 1800 V and specific on-resistance of 1.9 mΩ cm2 have been realized through ion implantation isolation. The planarity of the device structure and field termination profile are keys to explain this increase in the breakdown voltage.
    Applied Physics Express 07/2012; 5(7):4202-. · 2.73 Impact Factor

Full-text (2 Sources)

View
13 Downloads
Available from
Sep 20, 2014