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Thermodynamics of AlN deposition by means of the aluminium‐trichloride‐ammonia process
Author(s) -
Arnold H.,
Biste L.,
Kaufmann Th.
Publication year - 1978
Publication title -
kristall und technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0023-4753
DOI - 10.1002/crat.19780130808
Subject(s) - ammonia , aluminium , chemistry , dissociation (chemistry) , homogeneous , substrate (aquarium) , yield (engineering) , inorganic chemistry , mixing (physics) , thermodynamics , materials science , metallurgy , organic chemistry , physics , oceanography , geology , quantum mechanics
Equilibrium yields for CVD of AlN dependent on the input ratio AlCl 3 /NH 3 and on temperature were computed (A) for AlCl 3 + NH 3 ⇋ AlN + 3 HCl; (B) for additional complexing AlCl 3 + NH 3 ⇋ AlCl 3 · NH 3 at substrate temperature which did not result in changes of yield above 900°C; (C) for AlCl 3 · NH 3 ⇋ AlN + 3 HCl corresponding to complete inhibition of dissociation near the substrate of the complex formed or preformed at lower temperature which resulted in considerably lower yields. A corresponding decrease of experimental results occurred within reactors having a long AlCl 3 –NH 3 ‐mixing zone at 350°C or AlCl 3 · NH 3 ‐input with respect to a reactor with a short mixing zone near to the substrate. The dissociation of the complex present in the former two cases was inhibited considerably. – This investigations demonstrate the additional influence of homogeneous reactions, which has to be regarded for CVD especially with complexing reactants in connection with the role of reactor geometry, a problem being increasingly discussed at present.