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Integration of a photon source into the AlGaN/GaN high election mobility transistor (HEMT) platform will realize the functionality of on-chip optical pumping of deep electron traps which suppress the dynamic performances of power HEMTs. Here, we report a Schottky-on-heterojunction light-emitting diode (SoH-LED) realized on the p-doping-free lateral AlGaN/GaN heterostructure. A physical mode based on hot electron induced surface states impact ionization was proposed to explain the hole generation and injection processes in this p-doping-free SoH-LED. Since the SoH-LED shares identical epitaxial structures with HEMT, integration of SoH-LED and HEMT requires no additional epi-layers during the wafer growth and minimum process modification during device fabrication. The SoH-LED structure was seamlessly integrated into the HEMT platform as an on-chip photon source. Experiment results showed that the SoH-LED photons can effectively assist the electron de-trapping processes from both of the surface and bulk deep traps, demonstrating the feasibility of using on-chip generated photons to improve the dynamic performances of AlGaN/GaN power HEMTs. [ABSTRACT FROM AUTHOR]

In this work, the Schottky-on-heterojunction light-emitting diodes (SoH-LED) are monolithically integrated with the AlGaN/GaN high-electron-mobility transistors (HEMT) on an AlGaN/GaN-on-Si platform commonly used for GaN lateral electronic devices. The on-chip electro-optic modulation is realized in a single device fabricated using HEMT-compatible process. Also, SoH-LED arrays are fabricated to demonstrate the on-chip addressable functionality with each SoH-LED pixel in the array individually controlled by the integrated HEMT. High-resolution micro-scale SoH-LED seven-segment displays are demonstrated to show the potential of using SoH-LEDs as a robust alternative for micro flat-panel displays. [ABSTRACT FROM AUTHOR]

The degradation of transient OFF-state leakage current in AlGaN/GaN HEMTs induced by ON-state gate overdrive was observed and studied. The OFF-state leakage current increases significantly with a pre- ON-state gate overdrive. It takes more than 30 s for the leakage current decay to its equilibrium level in dark. The decay processes follow a stretched-exponential law. We propose that this degradation corresponds to the persistent photoconductivity of GaN buffer induced by the electroluminescence during the Schottky gate overdrive. Both the ON-state gate overdrive bias and duration dependences of the OFF-states leakage degradation were studied. This work indicates that gate-protection is necessary to preserve low OFF-state leakage current and improve device reliability. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The threshold voltage ( VT) instability of metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) is investigated. In the enhancement-mode AlGaN/GaN MIS-HEMT fabricated by fluorine plasma implantation technique featuring Al2O3 gate dielectric, a hysteresis of 0.6 V in transfer characteristics is observed by quasi-static I - V (current-voltage) measurement, in which the gate bias is swept at a low rate (0.7 V/s). Pulsed transfer characteristics measurement, however, unveils much larger hysteresis under the same gate voltage swing. The VT-instability is attributed to the traps located at the dielectric/III-nitride interface as well as in the bulk of gate dielectric. It is proposed that pulsed measurement can count for the effect of fast traps (shallow traps) while the quasi-static measurement can only reflect slow traps (deep traps), and is more accurate for VT-instability evaluation. In addition, the existence of bulk traps is implied by a slow time-dependent shift of VT under large gate bias. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]