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Title: Substrate impact on the low-temperature growth of GaN thin films by plasma-assisted atomic layer deposition

Abstract

Gallium nitride (GaN) thin films were grown on Si (100), Si (111), and c-plane sapphire substrates at 200 °C via hollow-cathode plasma-assisted atomic layer deposition (HCPA-ALD) using GaEt{sub 3} and N{sub 2}/H{sub 2} plasma as group-III and V precursors, respectively. The main aim of the study was to investigate the impact of substrate on the material properties of low-temperature ALD-grown GaN layers. Structural, chemical, and optical characterizations were carried out in order to evaluate and compare film quality of GaN on different substrates. X-ray reflectivity measurements showed film density values of 5.70, 5.74, and 5.54 g/cm{sup 3} for GaN grown on Si (100), Si (111), and sapphire, respectively. Grazing incidence x-ray diffraction measurements exhibited hexagonal wurtzite structure in all HCPA-ALD grown GaN samples. However, dominant diffraction peak for GaN films grown on Si and sapphire substrates were detected differently as (002) and (103), respectively. X-ray diffraction gonio scans measured from GaN grown on c-plane sapphire primarily showed (002) orientation. All samples exhibited similar refractive index values (∼2.17 at 632 nm) with 2–3 at. % of oxygen impurity existing within the bulk of the films. The grain size was calculated as ∼9–10 nm for GaN grown on Si (100) and Si (111) samples while itmore » was ∼5 nm for GaN/sapphire sample. Root-mean-square surface roughness values found as 0.68, 0.76, and 1.83 nm for GaN deposited on Si (100), Si (111), and sapphire, respectively. Another significant difference observed between the samples was the film growth per cycle: GaN/sapphire sample showed a considerable higher thickness value when compared with GaN/Si samples, which might be attributed to a possibly more-efficient nitridation and faster nucleation of sapphire surface.« less

Authors:
; ;  [1]
  1. National Nanotechnology Research Center (UNAM), Bilkent University, Bilkent, Ankara 06800, Turkey and Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, Ankara 06800 (Turkey)
Publication Date:
OSTI Identifier:
22592878
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 34; Journal Issue: 4; Other Information: (c) 2016 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 42 ENGINEERING; COMPARATIVE EVALUATIONS; DEPOSITION; GALLIUM NITRIDES; GRAIN SIZE; HOLLOW CATHODES; LAYERS; PLASMA; REFRACTIVE INDEX; ROUGHNESS; SAPPHIRE; SUBSTRATES; TEMPERATURE RANGE 0065-0273 K; THIN FILMS; X-RAY DIFFRACTION

Citation Formats

Kizir, Seda, Haider, Ali, and Biyikli, Necmi, E-mail: biyikli@unam.bilkent.edu.tr. Substrate impact on the low-temperature growth of GaN thin films by plasma-assisted atomic layer deposition. United States: N. p., 2016. Web. doi:10.1116/1.4953463.
Kizir, Seda, Haider, Ali, & Biyikli, Necmi, E-mail: biyikli@unam.bilkent.edu.tr. Substrate impact on the low-temperature growth of GaN thin films by plasma-assisted atomic layer deposition. United States. doi:10.1116/1.4953463.
Kizir, Seda, Haider, Ali, and Biyikli, Necmi, E-mail: biyikli@unam.bilkent.edu.tr. Fri . "Substrate impact on the low-temperature growth of GaN thin films by plasma-assisted atomic layer deposition". United States. doi:10.1116/1.4953463.
@article{osti_22592878,
title = {Substrate impact on the low-temperature growth of GaN thin films by plasma-assisted atomic layer deposition},
author = {Kizir, Seda and Haider, Ali and Biyikli, Necmi, E-mail: biyikli@unam.bilkent.edu.tr},
abstractNote = {Gallium nitride (GaN) thin films were grown on Si (100), Si (111), and c-plane sapphire substrates at 200 °C via hollow-cathode plasma-assisted atomic layer deposition (HCPA-ALD) using GaEt{sub 3} and N{sub 2}/H{sub 2} plasma as group-III and V precursors, respectively. The main aim of the study was to investigate the impact of substrate on the material properties of low-temperature ALD-grown GaN layers. Structural, chemical, and optical characterizations were carried out in order to evaluate and compare film quality of GaN on different substrates. X-ray reflectivity measurements showed film density values of 5.70, 5.74, and 5.54 g/cm{sup 3} for GaN grown on Si (100), Si (111), and sapphire, respectively. Grazing incidence x-ray diffraction measurements exhibited hexagonal wurtzite structure in all HCPA-ALD grown GaN samples. However, dominant diffraction peak for GaN films grown on Si and sapphire substrates were detected differently as (002) and (103), respectively. X-ray diffraction gonio scans measured from GaN grown on c-plane sapphire primarily showed (002) orientation. All samples exhibited similar refractive index values (∼2.17 at 632 nm) with 2–3 at. % of oxygen impurity existing within the bulk of the films. The grain size was calculated as ∼9–10 nm for GaN grown on Si (100) and Si (111) samples while it was ∼5 nm for GaN/sapphire sample. Root-mean-square surface roughness values found as 0.68, 0.76, and 1.83 nm for GaN deposited on Si (100), Si (111), and sapphire, respectively. Another significant difference observed between the samples was the film growth per cycle: GaN/sapphire sample showed a considerable higher thickness value when compared with GaN/Si samples, which might be attributed to a possibly more-efficient nitridation and faster nucleation of sapphire surface.},
doi = {10.1116/1.4953463},
journal = {Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films},
number = 4,
volume = 34,
place = {United States},
year = {Fri Jul 15 00:00:00 EDT 2016},
month = {Fri Jul 15 00:00:00 EDT 2016}
}