GaN Nanotube FET With Embedded Gate for High Performance, Low Power Applications

On the road of CMOS device continuously scaling, there are lots of challenges regarding the device structure and material engineering. GaN channel has recently been used in MOSFETs and achieved excellent performance. In this paper, we study a novel embedded gate GaN nanotube field effect transistor of 5 nm gate length with I
_ON
/I
_OFF
as high as 10
⁶
, and subthreshold swing (SS) as small as 64 mV/dec using Sentaurus TCAD simulation. The device can effectively improve subthreshold characteristics due to the GaN channel and embedded gate design. Compared with Si nanotube FET and GaN nanowire FET, GaN embedded nanotube FET exhibits low SS and high I
_ON
/I
_OFF
at the same channel thickness. GaN embedded nanotube FET has also been determined to superior temperature adaptability and performs better in terms of threshold voltage and subthreshold characteristics compared to Si nanotube FET at the same temperature. In addition, we investigated the impact of different lengths and thicknesses of the embedded gate on the subthreshold characteristics. As the length and thickness of the embedded gate are increased, SS and I
_ON
/I
_OFF
are improved. This excellent electrical performance demonstrates the possibility of GaN as a channel material in MOSFETs and embedded gate as an effective design to improve subthreshold characteristics, opening a new way for continued device scaling.