ABSTRACT
Gallium nitride transistors with high electron mobility (HEMT) have been studied by means of electrochemical capacitance–voltage (ECV) technique. The capacitance–voltage characteristics at various frequencies were measured; the free charge carrier depth distributions as well as the intensity of quantum well filling by charge carriers were obtained. The features of 2D electron gas (2DEG) appearance in GaN HEMT, related to spontaneous and piezoelectric polarisation, as well as factors affecting the density of free charge carriers in channel and the performance of GaN HEMTs were described in detail. The efficiency of ECV technique for quality control of both active and buffer layers of GaN HEMT heterostructures is shown. The calculation of 2DEG density for various technological parameters of the interface, such as mutual orientation of AlGaN/GaN layers and composition of AlxGa1-xN, is carried out taking into account piezoelectric effects.
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Notes on contributors
George Yakovlev
George Yakovlev is Ph.D., assistant at department of micro- and nanoelectronics of St. Petersburg State Electrotechnical University (LETI), specialist in the field of capacitive spectroscopy of semiconductors
Vasily Zubkov
Vasily Zubkov is Doctor of Sc., professor at department of micro- and nanoelectronics of St. Petersburg State Electrotechnical University (LETI), recognized specialist in the field of admittance spectroscopy and simulation of quantum-sized semiconductor heterostructures
Anna Solomnikova
Anna Solomnikova is Engineer at Department of micro- and nanoelectronics of St. Petersburg State Electrotechnical University (LETI), specialist in the field of atomic-force microscopy and admittance spectroscopy