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Title: Real-Time Synchrotron X-ray Studies of Low- and High-temperature Nitridation of c-plane Sapphire

Abstract

The plasma nitridation kinetics of c-plane sapphire at both low (200-300 {sup o}C) and high (750 {sup o}C) substrate temperatures was examined using grazing-incidence real-time x-ray diffraction, in situ x-ray reflection and in situ reflection high-energy electron diffraction (RHEED). These monitored the evolution of the nitride thickness, strain, and surface structure during nitridation. The evolution of the AlN(101{bar 0}) peak showed that the heteroepitaxial strain in the first layer of nitride is already significantly relaxed relative to the substrate. Subsequent layers grow with increasing relaxation. In both the high- and low-temperature nitridation cases, the results suggest that the early stage nitridation is governed by a complex nucleation and growth process. Nitridation at both temperatures apparently proceeds in a two-dimensional growth mode with the initial nucleating islands consisting of several monolayers which grow laterally. At low temperature the growth slows or even stops after impingement of the nucleating islands covering the surface, possibly due to low diffusivities through the existing layer. Initial formation and growth rates of nucleating islands at high temperatures are comparable to those at low temperatures, but subsequent growth into the substrate is significantly enhanced over the low temperature case, consistent with activation energies of 0.1-0.25 eV.

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930605
Report Number(s):
BNL-80911-2008-JA
Journal ID: ISSN 1098-0121; TRN: US0901417
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review B: Condensed Matter and Materials Physics; Journal Volume: 74
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACTIVATION ENERGY; ELECTRON DIFFRACTION; GRAZING INCIDENCE TOMOGRAPHY; IMPINGEMENT; KINETICS; NITRIDATION; NITRIDES; NUCLEATION; PLASMA; REFLECTION; RELAXATION; SAPPHIRE; STRAINS; SUBSTRATES; SYNCHROTRON RADIATION; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0065-0273 K; TEMPERATURE RANGE 0400-1000 K; THICKNESS; X-RAY DIFFRACTION; national synchrotron light source

Citation Formats

Wang,Y., Ozcan, A., Ozaydin, G., Ludwig, Jr., K., Bhattacharyya, A., Moustakas, T., Zhou, H., Headrick, R., and Siddons, P.. Real-Time Synchrotron X-ray Studies of Low- and High-temperature Nitridation of c-plane Sapphire. United States: N. p., 2006. Web. doi:10.1103/PhysRevB.74.235304.
Wang,Y., Ozcan, A., Ozaydin, G., Ludwig, Jr., K., Bhattacharyya, A., Moustakas, T., Zhou, H., Headrick, R., & Siddons, P.. Real-Time Synchrotron X-ray Studies of Low- and High-temperature Nitridation of c-plane Sapphire. United States. doi:10.1103/PhysRevB.74.235304.
Wang,Y., Ozcan, A., Ozaydin, G., Ludwig, Jr., K., Bhattacharyya, A., Moustakas, T., Zhou, H., Headrick, R., and Siddons, P.. Sun . "Real-Time Synchrotron X-ray Studies of Low- and High-temperature Nitridation of c-plane Sapphire". United States. doi:10.1103/PhysRevB.74.235304.
@article{osti_930605,
title = {Real-Time Synchrotron X-ray Studies of Low- and High-temperature Nitridation of c-plane Sapphire},
author = {Wang,Y. and Ozcan, A. and Ozaydin, G. and Ludwig, Jr., K. and Bhattacharyya, A. and Moustakas, T. and Zhou, H. and Headrick, R. and Siddons, P.},
abstractNote = {The plasma nitridation kinetics of c-plane sapphire at both low (200-300 {sup o}C) and high (750 {sup o}C) substrate temperatures was examined using grazing-incidence real-time x-ray diffraction, in situ x-ray reflection and in situ reflection high-energy electron diffraction (RHEED). These monitored the evolution of the nitride thickness, strain, and surface structure during nitridation. The evolution of the AlN(101{bar 0}) peak showed that the heteroepitaxial strain in the first layer of nitride is already significantly relaxed relative to the substrate. Subsequent layers grow with increasing relaxation. In both the high- and low-temperature nitridation cases, the results suggest that the early stage nitridation is governed by a complex nucleation and growth process. Nitridation at both temperatures apparently proceeds in a two-dimensional growth mode with the initial nucleating islands consisting of several monolayers which grow laterally. At low temperature the growth slows or even stops after impingement of the nucleating islands covering the surface, possibly due to low diffusivities through the existing layer. Initial formation and growth rates of nucleating islands at high temperatures are comparable to those at low temperatures, but subsequent growth into the substrate is significantly enhanced over the low temperature case, consistent with activation energies of 0.1-0.25 eV.},
doi = {10.1103/PhysRevB.74.235304},
journal = {Physical Review B: Condensed Matter and Materials Physics},
number = ,
volume = 74,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}