ABSTRACT
In 1963, Complementary Metal Oxide Semiconductor technology was introduced by Frank Wanlass. CMOS technology is an organization of two types of MOSFET such as P-type and N-type. CMOS technology has dominated the silicon industry due to various advantages. Initially in this chapter, we introduce the limitations of downscaling MOSFET devices which gave rise to short channel effects: Drain Induced Barrier Lowering, threshold roll-off, high leakage current and limits the subthreshold voltage to 60mV/dec. In order to overcome the disadvantages of conventional MOSFET device, a promising device Tunnel Field Effect Transistor was reported. The chapter is continued with the basic structure of the homojunction Double Gate (DG)TFET device. The DGTFET has shown less ON-state performance. Thus, to improve the ON-state performance of the TFET device multigate TFET devices, Gate All Around TFET and gate engineering is reported. Further, we move on to the different materials used for the formation of heterojunction TFET. Heterojunction TFET devices exhibit high forward gain and low reverse gain compared to the homojunction TFETs. And also, band-gap alignment is flexible based on the applications. The combination of silicon with other semiconductors for the formation of heterojunction provides a higher tuning of band-gap than silicon material technology. HeteroJunction Multigate TFET devices such as Double Gate(DG) HJTFET and Gate All Around HJTFET. The operation of the DG HJTFET and the advantages of the device will be discussed. The gate control of the HJTFET device is increased by a cylindrical gate that covers the substrate in all directions. Due to the increase in gate control, the tunneling of electrons increases which further increases the drain current performance. The device structure and operation of the GateAll-Around HJTFET will be discussed in detail. The chapter is further continued with the gate engineering HJTFET devices. Gate engineering is the usage of more than one material across the gate terminal which improves the performance of the device. The gate engineering is used for the Multigate and Gate-All-Around HJTFET devices. The gate engineering HJTFET devices include Double Material Double Gate(DMDG)HJTFET, Triple Material Double Gate (TMDG) HJTFET, Double Material Surrounding Gate(DMSG) HJTFET, and Triple Material Surrounding Gate (TMSG) HJTFET are explained along with device structure and its advantages. Thus, this chapter intends to study the device structure, multigate, gate engineering, electrostatic characteristics, and applications of heterojunction TFET devices
