Because of its poor thermal conductivity, the application of SiO2 insulating layer in highpower, high-temperature logic devices is limited by the self-heating effect [1]. The overheating of such devices could cause the degradation of the operations and the reduction of the device lifetime. Therefore, it is important to develop new insulating materials with good thermal conductivity and high dielectric constants. Aluminum nitride (AlN) exhibits a high thermal conductivity, ten times higher than SiO2 (~17 Wm−1K−1 [2]), low thermal expansion coefficient, a dielectric constant larger than 10, small dielectric loss and good stability at high temperatures (up to 1400°C) [3, 4]. Therefore, the use of AlN layer as gate dielectric should reduce the influence of the self-heating effect observed in traditional devices. AlN has a wide energy band gap of approximately 6.2 eV being an alternative material to be used in transparent electronics as gate dielectric. Fully transparent transistors based on indium gallium zinc oxide [5] as channel semiconductor were obtained using magnetron sputtering in RF regime and photolithography patterning (the staggered bottom-gate transistors have the channel length ratio of 20 μm architecture). Here we explore the thermal stability of the AlN based transistors. The influence of thermal treatment upon the electrical properties (capacity, dielectric losses, and pyroelectric coefficient vs. temperature) of the AlN layers is assed in order to establish its suitability for micro-electronics working in high temperatures conditions.