Si impurity concentration in nominally undoped Al0.7Ga0.3N grown in a planetary MOVPE reactor

J. Jeschke, A. Knauer, M. Weyers

Published in:

J. Cryst. Growth, vol. 483, pp. 297-300 (2018).

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Abstract:

The unintentional silicon incorporation during the metalorganic vapor phase epitaxy (MOVPE) of nominally undoped Al0.7Ga0.3N in a Planetary Reactor under various growth conditions was investigated. Dependent on growth temperature, pressure and V/III ratio, Si concentrations of below 1 × 1016 up to 4 × 1017 cm-3 were measured. Potential Si sources are discussed and, by comparing samples grown in a SiC coated reactor setup and in a TaC coated setup, the SiC coatings in the reactor are identified as the most likely source for the unintentional Si doping at elevated temperatures above 1080 °C. Under identical growth conditions the background Si concentration can be reduced by up to an order of magnitude when using TaC coatings.

Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany

Keywords:

A1. Impurities, A1. Desorption, A3. Metal organic chemical vapor deposition, B1. Nitrides.