TY - JOUR
T1 - Evolution of threading dislocation density and stress in GaN films grown on (111) Si substrates by metalorganic chemical vapor deposition
AU - Weng, X.
AU - Acord, J. D.
AU - Jain, A.
AU - Dickey, E. C.
AU - Redwing, J. M.
N1 - Funding Information:
This work was supported by The Penn State Electro-Optics Center, the Lehigh-Penn State Center for Optical Technologies, and the National Science Foundation under Grant Nos. ECS-0093742 and DMR-0606451.
PY - 2007/4
Y1 - 2007/4
N2 - We have studied the evolution of threading dislocations (TDs), stress, and cracking of GaN films grown on (111) Si substrates using a variety of buffer layers including thin AlN, compositionally graded Al x Ga 1-x N (0 ≤ x ≤ 1), and AlN/Al y Ga 1-y N/Al x Ga 1-x N (0 ≤ x ≤ 1, y = 0 and 0.25) multilayer buffers. We find a reduction in TD density in GaN films grown on graded Al x Ga 1-x N buffer layers, in comparison with those grown directly on a thin AlN buffer layer. Threading dislocation bending and annihilation occurs in the region in the graded Al x Ga 1-x N grown under a compressive stress, which leads to a decrease of TD density in the overgrown GaN films. In addition, growing a thin AlN/Al y Ga 1-y N bilayer prior to growing the compositionally graded Al x Ga 1-x N buffer layer significantly reduces the initial TD density in the Al x Ga 1-x N buffer layer, which subsequently further reduces the TD density in the overgrown GaN film. In-situ stress measurements reveal a delayed compressive-to-tensile stress transition for GaN films grown on graded Al x Ga 1-x N buffer layers or multilayer buffers, in comparison to the film grown on a thin AlN buffer layer, which subsequently reduces the crack densities in the films.
AB - We have studied the evolution of threading dislocations (TDs), stress, and cracking of GaN films grown on (111) Si substrates using a variety of buffer layers including thin AlN, compositionally graded Al x Ga 1-x N (0 ≤ x ≤ 1), and AlN/Al y Ga 1-y N/Al x Ga 1-x N (0 ≤ x ≤ 1, y = 0 and 0.25) multilayer buffers. We find a reduction in TD density in GaN films grown on graded Al x Ga 1-x N buffer layers, in comparison with those grown directly on a thin AlN buffer layer. Threading dislocation bending and annihilation occurs in the region in the graded Al x Ga 1-x N grown under a compressive stress, which leads to a decrease of TD density in the overgrown GaN films. In addition, growing a thin AlN/Al y Ga 1-y N bilayer prior to growing the compositionally graded Al x Ga 1-x N buffer layer significantly reduces the initial TD density in the Al x Ga 1-x N buffer layer, which subsequently further reduces the TD density in the overgrown GaN film. In-situ stress measurements reveal a delayed compressive-to-tensile stress transition for GaN films grown on graded Al x Ga 1-x N buffer layers or multilayer buffers, in comparison to the film grown on a thin AlN buffer layer, which subsequently reduces the crack densities in the films.
UR - http://www.scopus.com/inward/record.url?scp=34249015792&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34249015792&partnerID=8YFLogxK
U2 - 10.1007/s11664-006-0055-7
DO - 10.1007/s11664-006-0055-7
M3 - Article
AN - SCOPUS:34249015792
SN - 0361-5235
VL - 36
SP - 346
EP - 352
JO - Journal of Electronic Materials
JF - Journal of Electronic Materials
IS - 4
ER -