Theoretical investigation of point defects, their agglomerates and their effects on optical properties in irradiated silicon carbide by means of quantum mechanical calculations  Page description

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Details of project

  
Identifier
38357
Type F
Principal investigator Gali, Ádám
Title in Hungarian Besugárzással létrehozott ponthiba és ponthibaagglomerátumok, valamint ezek optikai tulajdonságokra gyakorolt hatásának elméleti vizsgálata szilíciumkarbidban
Title in English Theoretical investigation of point defects, their agglomerates and their effects on optical properties in irradiated silicon carbide by means of quantum mechanical calculations
Panel Physics
Department or equivalent Department of Atomic Physics (Budapest University of Technology and Economics)
Participants Aradi, Bálint
Starting date 2002-01-01
Closing date 2005-12-31
Funding (in million HUF) 3.760
FTE (full time equivalent) 0.00
state closed project





 

Final report

  
Results in Hungarian
Kutatásaimban három fontos atomi folyamatra mutattam rá a besugárzott SiC-ban: az antisite-ok, a vakanciák, valamint a szén-intersticiálisok aggregációja. A számításaim részben egy időben mutatták ki a kísérletekkel együtt ezeket, vagy előre megjósolták. Megmutattam, hogy ezen hibák általában elektromosan aktívak, és korábban már részben észlelték azokat. A divakancia azonosítása PRL-ben jelent meg, illetve szén antisite-vakancia pár azonosítása is ugyanolyan fontos eredmény mind elméleti mind gyakorlati szempontból. A p-típusú adalékok és szén-intersticiálisok komplexumai szintén létrehozhatnak termikusan stabil, parazita hibákat számításaink szerint a besugárzott SiC-ban, amelyet később a kísérletek is megerősítettek. A fentiek mellett a foszfor donor CVD-beli növesztésének megértéséhez, valamint az azonosításához járultam lényegesen hozzá. Tisztáztuk, hogy melyek a SiC/SiO2 határfelületen előforduló legfontosabb hibák, és azok hogyan befolyásolják a SiC elektronszerkezetét. Emellett megvizsgáltuk egy hipotetikus szuperrács elektromos és optikai tulajdonságait, amely ú.n. polaritásváltásos hibákat tartalmaz. Megmutattuk, hogy nm alatti ultravékony 2D elektron- és lyukgázt lehet így létrehozni. Emellett ez egy polarizációs szuperrácsot alkot, ahol az effektív tiltottsáv-szélességet lehet szabályozni. Emiatt különleges nem-lineáris optikai tulajdonságokkal is rendelkezik. Számításaink szerint atomi rétegleválasztás módszerével a fenti szuperrács megvalósítható.
Results in English
In my studies I pointed out three basic processes at atomistic level in irradiated SiC: aggregation of antisites, vacancies and carbon self-interstitials. This was shown partly simultanuously with the experiments, or those have been predicted by my calculations. I found that these defects are usually electrically active, and some of them have been already detected. The identification of divacancy was published in PRL, while the identification of carbon antisite-vacancy pair is also very important result from both theoretical and technological point of view. Our calculations indicated that the complex of p-type dopants and carbon interstitials can also form thermally stable, parasite defects in irradiated SiC, that has been confirmed later in the experiments. Beside that our calculation significantly contributed to the understanding of doping of phosphorous in CVD chamber as well as in its identifiation. We found the most important defects at the interface of SiC/SiO2 and how those affected the electronic structure of SiC. In addition, we have investigated the electrical and optical properties of an hypothetical superlattice that contains so-called polarity-change defects. We showed that 2D electron and hole gases are formed under nm thickness. This forms also a polarization superlattice, in that the effective band gap can be controlled. It possesses peculiar non-linear optical properties. Our calculations showed that this superlattice can be grown by atomic layer epitaxy.
Full text http://real.mtak.hu/564/
Decision
Yes





 

List of publications

  
A. Gali, T. Hornos, P. Deák, N.T. Son, E. Janzén, and W.J. Choyke: Theoretical Investigations of Complexes of p-Type Dopants and Carbon Interstitial in SiC: Bistable, Negative-U Defects, Material Science Forum, vol. 483-485, pp. 519-522, 2005
P. Deák, B. Aradi, A. Gali, and U. Gerstmann: Some like it shallower – p-type doping in SiC, Physica Status Solidi B, vol. 235, pp. 139-145, 2003
A. Gali, T. Hornos, P. Deák, N.T. Son, E. Janzén, and W.J. Choyke: Activation of shallow boron acceptor in C/B co-implanted silicon carbide -- a theoretical study, Appl. Phys. Lett., vol. 86, 102108 (2005)., 2005
A. Gali, P. Deák, P. Ordejón, N. T. Son, E. Janzén, and W. J. Choyke: Aggregation of carbon interstitials in silicon carbide: A theoretical study, Physical Review B, vol. 68, 125201, 2003
N.T. Son, P. Carlsson, J. ul Hassan, E. Janzén, T. Umeda, J. Isoya, A. Gali, M. Bockstedte, N. Morishita, T. Ohshima, and H. Itoh: Divacancy in 4H-SiC, Physical Review Lett., vol. 95, 055501, 2006
A. Gali, N. T. Son, and E. Janzén: Electrical characterization of metastable carbon clusters in SiC – a theoretical study, Physical Review B, vol. 73, 033204, 2006
P. Deák, B. Aradi, A. Gali, U. Gerstmann, and W. J. Choyke: A shallow acceptor complex in 4H-SiC: AlSi-NC-AlSi complex, Mater. Sci. Forum, vol. 433-436, pp. 523-526, 2003
A. Gali, P. Deák, I.G. Ivanov, F.H.C. Carlsson, N.T. Son, E. Janzén, and W. J. Choyke: Correlation between the anti-site pair and the DI center in SiC, Physical Review B, vol. 67, 155203, 2003
A. Gali, P. Deák, N. T. Son, and E. Janzén: Hydrogen passivation of nitrogen in SiC, Appl. Phys. Lett., vol. 83, 1385-1387, 2003
A. Gali, P. Deák, N. T. Son, and E. Janzén: Possibility for the electrical activation of the carbon antisite by hydrogen in SiC, Physical Review B, vol. 71, 035213, 2005
P. Deák, A. Gali, and B. Aradi: Hydrogen in SiC (3rd Chapter), Recent Major Advances in SiC edited by W. J. Choyke, H. Matsunami, and G. Pensl (Springer-Verlag Berlin Heidelberg 2004), 57-88 o., 2004
J. M. Knaup, P. Deák, Th. Frauenheim, A. Gali, Z. Hajnal, and W. J. Choyke: Theoretical study of the mechanism of dry oxidation of 4H-SiC, Physical Review B, vol. 71, 235321, 2005
T. Umeda, N. T. Son, J. Isoya, E. Janzén, T. Ohshima, N. Morishita, H. Itoh, A. Gali, and M. Bockstedte: The carbon antisite-vacancy pair: a major carrier compensating center in 4H-SiC, Physical Review Lett., beküldve, 2006
T. Hornos, A. Gali, R. P. Devaty, and W. J. Choyke: Doping of phosphorus in chemical-vapor-deposited silicon carbide layers: A theoretical study, Appl. Phys. Lett., vol. 87, 212114, 2005
N. T. Son, A. Henry, J. Isoya, M. Katagiri, T. Umeda, A. Gali, and E. Janzén: Electron paramagnetic resonance and theoretical studies of shallow phosphorous centers in 3C-, 4H- and 6H-SiC, Phys. Rev. B, vol. 73, 075201, 2006
A. Gali, T. Hornos, P. Deák, N. T. Son, E. Janzén, and W. J. Choyke: Bistable, negative-U complexes of the aluminum acceptor with carbon self-interstitials in SiC, Physical Review B, beküldve, 2006
P. Deák, A. Gali, A. Buruzs, and Th. Frauenheim: Possibility for a new type of superlattice in silicon carbide, Physical Review Lett., beküldve, 2006
F. Yan, R. P. Devaty, W. J. Choyke, A. Gali, I. B. Bhat and D. J. Larkin: Evidence for Phosphorus on Carbon and Silicon Sites in 6H and 4H SiC, Mater. Sci Forum, in print, 2006
A. Gali, P. Deák, J.-L. Monge, J. von der Bardeleben, N. T. Son, and E. Janzén: Calculation of hyperfine constants of defects in SiC, Mater. Sci Forum, vol. 433-436, pp. 511-514, 2003
A. Gali, M. Bockstedte, N. T. Son, T. Umeda, J. Isoya, and E. Janzén: Divacancy and its identification: theory, Mater. Sci. Forum, in print, 2006
M. Bockstedte, A. Gali, T. Umeda, N.T. Son, J. Isoya,and E. Janzén: Signature of the negative Carbon Vacancy-Antisite complex, Mater. Sci. Forum, in print, 2006
A. Gali, M. Bockstedte, N. T. Son, T. Umeda, J. Isoya, and E. Janzén: Divacancy and its identification: theory, Mater. Sci. Forum, in print, 2006



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