Investigation of InAlN/GaN Double Channel HEMTs for Improved Linearity

Abstract

This work thoroughly analyzed and studied the natural benefits of InAlN/GaN double channel (DC) HEMTs over single channel (SC) HEMTs in terms of increased linearity. When the drain-source current (I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ds</inf> ) is increased in an SC-HEMT, a strong electric field (E-field) will intensify the carrier scattering effect, which causes severe mobility (μ) degradation. Based on the above, combined with a sharp increase in source access resistance (R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</inf> ), causes the non-intrinsic transconductance to roll off quickly, making transconductance (G <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf> ) flattening difficult to accomplish. Due to its strongly polarized material, a thin barrier was adopted to provide enough carrier concentration, which improves gate control ability, and its double-channel structure, which offers additional carrier transport channels and disperses the channel E-field distribution, the InAlN/GaN DC-HEMT effectively addresses the aforementioned issues. Furthermore, the theoretically calculated OIP3 value of this device is constant over a large range of gate-source voltage (V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gs</inf> ), making it a workable option for enhancing the linearity of power microwave GaN-based HEMTs.