A novel β ‐Ga 2 O 3 HEMT with f T of 166 GHz and X‐band P OUT of 2.91 W/mm

In this paper, a novel β ‐Ga 2 O 3 high electron mobility transistor (BGO‐HEMT) with record‐high intrinsic unity current gain cut‐off frequency ( f T ) of 166 GHz and RF output power ( P OUT ) of 2.91 W/mm is demonstrated through 2D device simulations using an appropriate negative differential mobility model. The highly scaled proposed device uses 10 nm AlN barrier layer on 50 nm β ‐Ga 2 O 3 buffer with gate‐length ( L G ) of 50 nm and aspect‐ratio (gate length to barrier thickness) of 5 ensures significant gain in high‐frequency performance. The novel device design offers very low access and dynamic resistance due to highly doped n + access regions, and a finite gap between ohmic contacts and barrier layer to mitigate source choking effect. The device's superior DC and RF performance is well supported by large two‐dimensional electron gas (2DEG) density ( n s ) of the order of 10 13 cm −2 due to large band discontinuity in AlN/ β ‐Ga 2 O 3 heterostructure and highly polarized AlN material. The device shows maximum drain current density ( I DMAX ) of ~11.5 A/mm and peak transconductance ( g m ) of 0.917 S/mm at V DS = 15 V and V GS = 0 and − 7 V respectively. Furthermore, the term 2π ( f T × L G ) for the device shows a value of 0.5 × 10 7 cm/s, very close to v sat of 1.5 × 10 7 cm/s in β ‐Ga 2 O 3 . These promising results enhance the potential of β ‐Ga 2 O 3 for future high power RF and microwave applications.