Impact of N2 plasma power and duration on AlGaN/GaN HEMT

Romero Rojo, Fátima and Jiménez, A. and González-Posada Flores, Francisco and Martin Horcajo, Sara and Calle Gómez, Fernando and Muñoz Merino, Elias (2011). Impact of N2 plasma power and duration on AlGaN/GaN HEMT. In: "9th International Conference on Nitride Semiconductors", 10/07/2011 - 15/07/2011, Glasgow, UK. pp..

Description

Title: Impact of N2 plasma power and duration on AlGaN/GaN HEMT
Author/s:
  • Romero Rojo, Fátima
  • Jiménez, A.
  • González-Posada Flores, Francisco
  • Martin Horcajo, Sara
  • Calle Gómez, Fernando
  • Muñoz Merino, Elias
Item Type: Presentation at Congress or Conference (Poster)
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

urface treatments have been recently shown to play an active role in electrical characteristics in AlGaN/GaN HEMTs, in particular during the passivation processing [1-4]. However, the responsible mechanisms are partially unknown and further studies are demanding. The effects of power and time N2 plasma pre-treatment prior to SiN deposition using PE-CVD (plasma enhanced chemical vapour deposition) on GaN and AlGaN/GaN HEMT have been investigated. The low power (60 W) plasma pre-treatment was found to improve the electronic characteristics in GaN based HEMT devices, independently of the time duration up to 20 min. In contrast, high power (150 and 210 W) plasma pretreatment showed detrimental effects in the electronic properties (Fig. 1), increasing the sheet resistance of the 2DEG, decreasing the 2DEG charge density in AlGaN/GaN HEMTs, transconductance reduction and decreasing the fT and fmax values up to 40% respect to the case using 60 W N2 plasma power. Although AFM (atomic force microscopy) results showed AlGaN and GaN surface roughness is not strongly affected by the N2-plasma, KFM (Kelvin force microscopy) surface analysis shows significant changes in the surface potential, trending to increase its values as the plasma power is higher. The whole results point at energetic ions inducing polarization-charge changes that affect dramatically to the 2-DEG charge density and the final characteristics of the HEMT devices. Therefore, we conclude that AlGaN surface is strongly sensitive to N2 plasma power conditions, which turn to be a key factor to achieve a good surface preparation prior to SiN passivation.

More information

Item ID: 12931
DC Identifier: http://oa.upm.es/12931/
OAI Identifier: oai:oa.upm.es:12931
Deposited by: Memoria Investigacion
Deposited on: 07 Nov 2012 12:36
Last Modified: 21 Apr 2016 12:15
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