Simulation Insights of AlGaN/GaN HEMT Structure Optimization for Biosensor Applications

This article examines the effects of gate-to-drain length (L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GD</inf>), source-to-gate length (L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SG</inf>), gate length (L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</inf>), and environmental conditions like temperature on transfer, transconductance, and output characteristics of HEMT. The Silvaco Atlas device simulation tool was used to retrieve the results. As temperature, source-to-gate length, and gate length grow, peak transconductance, drain saturation current and device ON current decrease. As gate-to-drain length increases, so do peak transconductance, drain saturation current, and device ON current. Variations in the device's L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</inf>, L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SG</inf>, L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GD</inf>, and environmental conditions like temperature alter the device's current characteristics, which can be utilized as a biosensor sensing metric. HEMT-based biosensors, like AlGaN/GaN MOSHEMTs, are highly sensitive to device geometry (L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</inf>, L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SG</inf>, and L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GD</inf>). All these factors contribute to the overall detection accuracy, sensitivity, response time, and power consumption.