In this paper, a novel low leakage saddle junctionless field effect transistor with assistant gate is proposed. Its electrical properties have been extensively investigated by studying the influence resulting from variation of design parameters, such as the thickness of assistant gate, oxide layer thickness between the main and assistant gate, extension height of S/D contact, and the voltage of assistant gate. Compared with conventional structure, the proposed saddle junctionless field effect transistor with assistant gate shows much better performance at off state. The leakage current is effectively restrained, and the I on -I off ratio is largely improved. Design parameter optimization has also been performed.

A novel high-performance rectangular gate U channel FET (RGUC FET) for extreme integrated distance between source and drain contacts is proposed in this paper. The RGUC FET represents nearly ideal subthreshold characteristics till the distance between source/drain (S/D) contacts reduced to 2 nm. Different from the other recessed or U-shaped channel-based FETs, the gate contacts do not need to be formed in the recessed region but only in a layer of spacer for the insulation between the two vertical parts on both sides of the U channel. Its structural advantages make it possible to be applied to manufacture integrated circuits with higher integration for extreme integrated distance between source and drain contacts. The electrical properties of the RGUC FET were scrupulously investigated by studying the influence of design parameters including the horizontal distance between S/D contacts, the extension height of S/D region, and the thickness and material of the gate oxide layer. The electrical properties of the RGUC FET are verified by quantum simulation. Compared to the other non-planner channel multi-gate FETs, the novel RGUC FET is suitable for higher integration.