Double gate graphene nanoribbon field effect transistor with single halo pocket in channel region

• Doping type of halo and source/drain regions are the same.
• Halo pocket creates a step in potential profile.
• Band to band tunneling is reduced and ON/OFF current ratio increased.
• Proposed structure has superior ambipolar characteristics.
• The proposed structure has lower PDP and higher speed.

A new structure for graphene nanoribbon field-effect transistors (GNRFETs) is proposed and investigated using quantum simulation with a nonequilibrium Green's function (NEGF) method. Tunneling leakage current and ambipolar conduction are known effects for MOSFET-like GNRFETs. To minimize these issues a novel structure with a simple change of the GNRFETs by using single halo pocket in the intrinsic channel region, “Single Halo GNRFET (SH-GNRFET)”, is proposed. An appropriate halo pocket at source side of channel is used to modify potential distribution of the gate region and weaken band to band tunneling (BTBT). In devices with materials like Si in channel region, doping type of halo and source/drain regions are different. But, here, due to the smaller bandgap of graphene, the mentioned doping types should be the same to reduce BTBT. Simulations have shown that in comparison with conventional GNRFET (C-GNRFET), an SH-GNRFET with appropriately halo doping results in a larger ON current (Ion), smaller OFF current (Ioff), a larger ON–OFF current ratio (Ion/Ioff), superior ambipolar characteristics, a reduced power–delay product and lower delay time.

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