Effect of high-k dielectric HfO2 on performance of AlGaN/GaN based MOSHEMT for RF applications

This paper investigates the effect of high-k gate dielectric materials on DC, RF and noise parameters of AlGaN/GaN MOSHEMT. Hafnium dioxide (HfO 2 ) is used as high-k gate dielectric material to study the proposed MOSHEMT and compared with MOSHEMT having alumina (Al 2 O 3 ) as gate dielectric. The Transition Frequency ( f T ) is 114 (105) GHz of MOSHEMT with HfO 2 (Al 2 O 3 ) and the Maximum Oscillation Frequency ( f MAX ) is 192 (177) GHz of MOSHEMT with HfO 2 (Al 2 O 3 ). The obtained f T and f MAX signify that the MOSHEMT with HfO 2 can be operated at higher frequency which can cover Ku, K, Ka, V, W, and lower tierce of millimeter wave (mmWave). Therefore, the noise parameters such as minimum noise figure ( NF MIN ), noise resistance ( R n ) and optimum reflection coefficient (Г OPT ) have been estimated for the frequency range from 10 to 120 GHz. Maximum drain current ( I DMAX ), threshold voltage ( V t ) and transconductance ( g m ) have been also estimated for the MOSHEMT with HfO 2 and Al 2 O 3 as gate dielectric layer. All the obtained results exhibit that the MOSHEMT with HfO 2 could be useful for higher frequency and low noise applications.