Simulation on AlN/GaN/AlN/GaN Planar HEMT and Fin-HEMT for Low-Voltage Applications

For low-voltage RF applications, in this letter, planar double-channel AlN/GaN HEMT (PDC HEMT) is researched based on the planar single-channel AIN/GaN HEMT (PSC HEMT). Compared with PSC HEMT, PDC HEMT enhances the output current density <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathrm{I}_{\mathrm{d}})$</tex> effectively, however the knee voltage <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathrm{V}_{\mathrm{k}})$</tex> increases. Subsequently, double-channel AIN/GaN HEMT with Fin structure (FDC HEMT) is researched with effectively increased electric field and reduced <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{\mathrm{k}}$</tex> The device with a Fin width <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathrm{W}_{\text{Fin}})$</tex> of 100 nm exhibits the lowest <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{\mathrm{k}}$</tex>, only 0.9 V. Both comparison of simulation results of PSC HEMT and PDC HEMT and the effect of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{W}_{\text{Fin}}$</tex> on Vi of FDC HEMT is exported in this letter. Simulation results show that PDC HEMT increases the maximum output current density (Id.max) to 3601 mA/mm, but the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{\mathrm{k}}$</tex> increases to 1.34 V. FDC HEMT effectively increases the electric field within the channel, reducing the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{\mathrm{k}}$</tex>. The FDC HEMT with 100 nm <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{W}_{\text{Fin}}$</tex> reduces <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{\mathrm{k}}$</tex> to 0.9 V. Therefore, PDC HEMT can effectively enhance the output current and FDC HEMT can effectively reduce <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{\mathrm{k}}$</tex>, which is beneficial to improving device performance.