Publications by    
Page 1  (11 Items)

1.  Crystallographic Growth Models of Wurtzite-Type Thin Films on 6H-SiC
H. Ohsato, K. Wada, T. Kato, C.J. Sun, and M. Razeghi
Materials Science Forum Vol. 389-393, no. 2, pp. 1489-1492.-- January 1, 2002
Epitaxial growth of GaN has been tried using various kinds of substrates so far. Of all the substrate, Al2O3 has been widely used for the GaN growth. Besides Al2O3, SiC is also expected as one of the most suitable substrates for the GaN growth, since SiC has a small mismatch in the lattice parameters with GaN and has good thermal stability under controlled atmospheres during the GaN growth. Both 6H-SiC and GaN having wurtzite structure belong to the same space group (P63mc). The lattice parameters are as follows: a=3.08, c=15.08 Å for 6H-SiC and a=3.19, c=5.18 Å for GaN. SiC has two opposite surface polarities along [001] direction. The main objective of our research was to establish a crystallographic growth model of GaN on the (001)6H-SiC with different polarities of Si and C surfaces.
 
2.  Simultaneous growth of two differently oriented GaN epilayers on (11.0) sapphire (II) a growth model of (00.1) and (10.0) GaN
T. Kato, P. Kung, A. Saxler, C.J. Sun, H. Ohsato, M. Razeghi and T. Okuda
-- January 1, 1998
 
3.  Morphology of Twinned GaN Grown on (11.0) Sapphire Substrates
T. Kato, P. Kung, A. Saxler, C.J. Sun, H. Ohsato, M. Razeghi and T. Okuda
-- January 1, 1997
 
4.  Simultaneous growth of two different oriented GaN epilayers on (11.0) sapphire (I) morphology and orientation
T. Kato, H. Ohsato, T. Okuda, P. Kung, A. Saxler, C.J. Sun, and M. Razeghi
-- January 1, 1997
 
5.  Exploration of entire range of III-V semiconductors and their device applications
M. Razeghi, Y.H. Choi, X. He, and C.J. Sun
-- January 1, 1995
 
6.  Thermal stability of GaN thin films grown on (0001) Al2O3, (0112) Al2O3 and (0001)Si 6H-SiC substrates
C.J. Sun, P. Kung, A. Saxler, H. Ohsato, E. Bigan, M. Razeghi, and D.K. Gaskill
Journal of Applied Physics 76 (1)-- July 1, 1994
Single crystals of GaN were grown on (0001), (0112) Al2O3 and (0001)Si 6H‐SiC substrates using an atmospheric pressure metalorganic chemical‐vapor‐deposition reactor. The relationship has been studied between the thermal stability of the GaN films and the substrate’s surface polarity. It appeared that the N‐terminated (0001) GaN surface grown on (0001)Si 6H‐SiC has the most stable surface, followed by the nonpolar (1120) GaN surface grown on (0112) Al2O3, while the Ga‐terminated (0001) GaN surface grown on (0001) Al2O3 has the least stable surface. This is explained with the difference in the atomic configuration of each of these surfaces which induces a difference in their thermal decomposition. reprint
 
7.  Crystallography of epitaxial growth of wurtzite-type thin films on sapphire substrates
P. Kung, C.J. Sun, A. Saxler, H. Ohsato, and M. Razeghi
Journal of Applied Physics 75 (9)-- May 1, 1994
In this article, we present a crystallographic model to describe the epitaxial growth of wurtzite‐type thin films such as gallium nitride (GaN) on different orientations of sapphire (Al2O3) substrates. Through this model, we demonstrate the thin films grown on (00⋅1)Al2O3 have a better epilayer‐substrate interface quality than those grown on (01⋅2)Al2O3. We also show the epilayer grown on (00⋅1)Al2O3 are gallium‐terminated, and both (00⋅1) and (01⋅2) surfaces of sapphire crystals are oxygen‐terminated. reprint
 
8.  A Crystallographic Model of (00*1) Aluminum Nitride Epitaxial Thin Film Growth on (00*1) Sapphire Substrate
C.J. Sun, P. Kung, A. Saxler, H. Ohsato, M. Razeghi, and K. Haritos
Journal of Applied Physics 75 (8)-- April 15, 1994
A direct comparison of the physical properties of GaN thin films is made as a function of the choice of substrate orientations. Gallium nitride single crystals were grown on (0001) and (011-bar 2) sapphire substrates by metalorganic chemical vapor deposition. Better crystallinity with fine ridgelike facets is obtained on the (011-bar 2) sapphire. Also lower carrier concentration and higher mobilities indicate both lower nitrogen vacancies and less oxygen incorporation on the (011-bar 2) sapphire. The results of this study show better physical properties of GaN thin films achieved on (011-bar 2) sapphire. reprint
 
9.  High Quality Aluminum Nitride Epitaxial Layers Grown on Sapphire Substrates
A. Saxler, P. Kung, C.J. Sun, E. Bigan and M. Razeghi
Applied Physics Letters 64 (3)-- January 17, 1994
In this letter we report the growth of high quality AlN epitaxial layers on sapphire substrates. The AlN grown on (00·1) sapphire exhibited a better crystalline quality than that grown on (01·2) sapphire. An x-ray rocking curve of AlN on (00·1) Al2O3 yielded a full width at half-maximum of 97.2 arcsec, which is the narrowest value reported to our knowledge. The AlN peak on (01·2) Al2O3 was about 30 times wider. The absorption edge measured by ultraviolet transmission spectroscopy for AlN grown on (00·1) Al2O3 was about 197 nm. reprint
 
10.  AlxGa1-xN Grown on (00*1) and (01*2) Sapphire
C.J. Sun, P. Kung, A. Saxler, H. Ohsato, and M. Razeghi
-- November 1, 1993
 
11.  Comparison of the Physical Properties of GaN Thin Films Deposited on (0112) and (0001) Sapphire Substrates
C.J. Sun and M. Razeghi
Applied Physics Letters 63 (7)-- August 16, 1993
A direct comparison of the physical properties of GaN thin films is made as a function of the choice of substrate orientations. Gallium nitride single crystals were grown on (0001) and (0112) sapphire substrates by metalorganic chemical vapor deposition. Better crystallinity with fine ridgelike facets is obtained on the (0112) sapphire. Also lower carrier concentration and higher mobilities indicate both lower nitrogen vacancies and less oxygen incorporation on the (0112) sapphire. The results of this study show better physical properties of GaN thin films achieved on (0112) sapphire. reprint
 

Page 1  (11 Items)