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Title: Accurate characterization and understanding of interface trap density trends between atomic layer deposited dielectrics and AlGaN/GaN with bonding constraint theory

Many dielectrics have been proposed for the gate stack or passivation of AlGaN/GaN based metal oxide semiconductor heterojunction field effect transistors, to reduce gate leakage and current collapse, both for power and RF applications. Atomic Layer Deposition (ALD) is preferred for dielectric deposition as it provides uniform, conformal, and high quality films with precise monolayer control of film thickness. Identification of the optimum ALD dielectric for the gate stack or passivation requires a critical investigation of traps created at the dielectric/AlGaN interface. In this work, a pulsed-IV traps characterization method has been used for accurate characterization of interface traps with a variety of ALD dielectrics. High-k dielectrics (HfO{sub 2}, HfAlO, and Al{sub 2}O{sub 3}) are found to host a high density of interface traps with AlGaN. In contrast, ALD SiO{sub 2} shows the lowest interface trap density (<2 × 10{sup 12 }cm{sup −2}) after annealing above 600 °C in N{sub 2} for 60 s. The trend in observed trap densities is subsequently explained with bonding constraint theory, which predicts a high density of interface traps due to a higher coordination state and bond strain in high-k dielectrics.
Authors:
; ;  [1]
  1. Department of Electrical and Computer Engineering, North Carolina State University, 2410 Campus Shore Drive, Raleigh, North Carolina 27695 (United States)
Publication Date:
OSTI Identifier:
22483074
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 24; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALUMINIUM OXIDES; ANNEALING; BONDING; DEPOSITION; DIELECTRIC MATERIALS; FIELD EFFECT TRANSISTORS; FILMS; GALLIUM NITRIDES; HAFNIUM OXIDES; HETEROJUNCTIONS; INTERFACES; LAYERS; SEMICONDUCTOR MATERIALS; SILICA; SILICON OXIDES; TRAPS