Thermal effects in Ni/Au and Mo/Au gate metallization AlGaN/GaN HEMT's reliability

Romero Rojo, Fátima and Uren, M. and Jiménez, A. and Dua, C. and Tadjer, Marko Jak and Cuerdo Bragado, Roberto and Calle Gómez, Fernando and Muñoz Merino, Elias (2011). Thermal effects in Ni/Au and Mo/Au gate metallization AlGaN/GaN HEMT's reliability. In: "9th International Conference on Nitride Semiconductors", 10/07/2011 - 15/07/2011, Glasgow, UK. pp..

Description

Title: Thermal effects in Ni/Au and Mo/Au gate metallization AlGaN/GaN HEMT's reliability
Author/s:
  • Romero Rojo, Fátima
  • Uren, M.
  • Jiménez, A.
  • Dua, C.
  • Tadjer, Marko Jak
  • Cuerdo Bragado, Roberto
  • Calle Gómez, Fernando
  • Muñoz Merino, Elias
Item Type: Presentation at Congress or Conference (Article)
Event Title: 9th International Conference on Nitride Semiconductors
Event Dates: 10/07/2011 - 15/07/2011
Event Location: Glasgow, UK
Title of Book: proceedings of 9th International Conference on Nitride Semiconductors
Date: 2011
Subjects:
Faculty: E.T.S.I. Telecomunicación (UPM)
Department: Ingeniería Electrónica
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

AlGaN/GaN high electron mobility transistors (HEMT) are key devices for the next generation of high-power, high-frequency and high-temperature electronics applications. Although significant progress has been recently achieved [1], stability and reliability are still some of the main issues under investigation, particularly at high temperatures [2-3]. Taking into account that the gate contact metallization is one of the weakest points in AlGaN/GaN HEMTs, the reliability of Ni, Mo, Pt and refractory metal gates is crucial [4-6]. This work has been focused on the thermal stress and reliability assessment of AlGaN/GaN HEMTs. After an unbiased storage at 350 o C for 2000 hours, devices with Ni/Au gates exhibited detrimental IDS-VDS degradation in pulsed mode. In contrast, devices with Mo/Au gates showed no degradation after similar storage conditions. Further capacitance-voltage characterization as a function of temperature and frequency revealed two distinct trap-related effects in both kinds of devices. At low frequency (< 1MHz), increased capacitance near the threshold voltage was present at high temperatures and more pronounced for the Ni/Au gate HEMT and as the frequency is lower. Such an anomalous “bump” has been previously related to H-related surface polar charges [7]. This anomalous behavior in the C-V characteristics was also observed in Mo/Au gate HEMTs after 1000 h at a calculated channel temperatures of around from 250 o C (T2) up to 320 ºC (T4), under a DC bias (VDS= 25 V, IDS= 420 mA/mm) (DC-life test). The devices showed a higher “bump” as the channel temperature is higher (Fig. 1). At 1 MHz, the higher C-V curve slope of the Ni/Au gated HEMTs indicated higher trap density than Mo/Au metallization (Fig. 2). These results highlight that temperature is an acceleration factor in the device degradation, in good agreement with [3]. Interface state density analysis is being performed in order to estimate the trap density and activation energy.

More information

Item ID: 12930
DC Identifier: http://oa.upm.es/12930/
OAI Identifier: oai:oa.upm.es:12930
Deposited by: Memoria Investigacion
Deposited on: 07 Nov 2012 12:53
Last Modified: 21 Apr 2016 12:15
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