DIAGNOSTICS OF ELECTRONIC PARAMETERS FOR ACTIVE AND BUFFER LAYERS OF GAN HEMT HETEROSTRUCTURES
The gallium nitride transistors with high electron mobility (HEMT) have been studied by means of electrochemical capacitance-voltage (ECV) technique. The capacitance-voltage characteristics and conductivity spectra at various frequencies were measured, the free charge carrier depth distributions were obtained, the spatial arrangement and quantum wells filling degree were determined. The features of 2D electron gas (2DEG) appearance in GaN HEMT, related to spontaneous and piezoelectric polarization, as well as the factors affecting on the density of free charge carriers in the channel and the performance of GaN HEMTs were described in detail. The efficiency of the ECV technique for quality control of both active and buffer layers of GaN HEMT heterostructures is shown. The calculation of the 2DEG density for various technological parameters of the interface, such as the mutual orientation of the AlGaN/GaN layers and the composition of AlxGa1-xN, is carried out taking into account piezoelectric effects.
Authors: Yakovlev G. Е., Zubkov V. I., Solomonov A. V
Keywords: Electrochemical capacitance-voltage profiling, ECV, HEMT, GaN, piezoelectric polarization
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