In this work we present results of electrical parameters characterization of high-voltage AlGaN/GaN high electron mobility transistors with ohmic and Schottky drain electrodes on silicon substrates. The use of Schottky-drain contacts improves breakdown voltage (V-BR), which was V-BR = 900 V for L-GD = 20 mu m in contrast to V-BR = 505 V for ohmic-drain contacts. Both types of transistors exhibit drain current density of 500 mA/mm and leakage current of 10 mu A/mm. Temperature-dependent characterization reveals a drain current density decrease with increasing temperature. The Schottky-drain HEMTs are characterized by lower increase of the R-on (Delta R-on = 250% at 200 degrees C) in comparison to ohmic drain contacts (Delta R-on = 340% at 200 degrees C) relative to the room temperature due to decrease of on-set voltage of Schottky-drain HEMTs. (C) 2015 Elsevier Ltd. All rights reserved.