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Saint Petersburg, Russia

Alexeev A.N.,NTO ZAO | Krasovitsky D.M.,Svetlana Rost ZAO | Petrov S.I.,NTO ZAO | Chaly V.P.,Svetlana Rost ZAO | And 2 more authors.
Semiconductors | Year: 2015

The specific features of how nitride HEMT heterostructures are produced by NH3 and plasma-assisted (PA) molecular-beam epitaxy (MBE) are considered. It is shown that the use of high-temperature AlN/AlGaN buffer layers grown with ammonia at extremely high temperatures (up to 1150°C) can drastically improve the structural perfection of the active GaN layers and reduce the dislocation density in these layers to values of 9 × 108−1 × 109 cm−2. The use of buffer layers of this kind makes it possible to obtain high-quality GaN/AlGaN heterostructures by both methods. At the same time, in contrast to ammonia MBE which is difficult to apply at T < 500°C (because of the low efficiency of ammonia decomposition), PA MBE is rather effective at low temperatures, e.g., for the growth of InAlN layers lattice-matched with GaN. The results obtained in the MBE growth of AlN/AlGaN/GaN/InAlN heterostructures by both PA-MBE and NH3-MBE with an extremely high ammonia flux are demonstrated. © 2015, Pleiades Publishing, Ltd. Source


Alexeev A.N.,NTO ZAO | Krasovitsky D.M.,Svetlana Rost ZAO | Petrov S.I.,NTO ZAO | Chaly V.P.,Svetlana Rost ZAO
Semiconductors | Year: 2012

The deposition of a multilayer buffer layer that includes a high-temperature AlN layer grown at a temperature above 1100°C has made it possible to reduce the dislocation density in a GaN layer by 1. 5-2 orders of magnitude to values in the range from 9 × 10 8 to 1 × 10 9 cm -2, compared with the case of growth on a thin low-temperature AlN nucleation layer. The decrease in the dislocation density causes a substantial increase in the electron mobility in the GaN layers to 600-650 cm 2 V -1 s -1, which is in agreement with the results of calculations and is indicative of the high crystalline perfection of the layers. © 2012 Pleiades Publishing, Ltd. Source

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