Modelling simulation and analysis of triple material quadruple gate and tri gate tunnel field effect transistors

Abstract

The micro electronic technology has been transformed to nano technology after a long duration due to consistent research that has taken place. Even though there were large complexity in design and implementation, there emerged a nano electronic device with excellent device performance. This includes high speed, high compatibility, high reliability, increased efficiency with enhanced performance characteristic at nominal price. newlineAfter conventional transistors and MOS transistors which were the basic building block of the electronic industry, the utter need for better performance electronic device paved way for intensive research in high performance miniaturized device.On having higher merits of scaling down of transistors, there are various undesirable effects such as higher current drive requirement, defects due to high packing density and high power consumption. These adverse effects are usually included in short channel effect. This is due to diminishing the length of the channel and should be removed or eliminated for proper operation of the device. newlineAn end to MOSFET scaling was reached when there was a constrain in sub threshold slope and leakage current. These factors hindered the MOSFET usage in low power requirements. Thus there was a search for novel device which could overcome the limitation that has been put forth by MOSFET.TFET was one such alternative which could be used instead of traditional MOSFET.TFET has a significant feature that it has a sub threshold swing lower than 60Mv/dec, higher stability and low leakage current. Device Modelling is required to know the basics behind the physics of the device at the nano meter regime. When this is known design and fabrication becomes easier.Analytical modelling is performed based on the constructional geometry, profile of doping and semiconductor equation which constitutes carrier transport mechanism and characteristics of materials. In this thesis dual benefit of both work function engineering and channel engineering are embodied and utilized to develop novel structure TFET. .By solving Poisson equation using parabolic approximation method, a physics dependent analytical model is generated. Parameters such as surface potential, Electric field and drain current are obtained and analyzed. Kane s model is used to extract drain current. The main limiting factor of TFET is its low ON current. Hence to improve the ON current a 3D analytical model of triple material Quadruple gate and triple material Tri gate structure is projected and analyzed. The proper choice of three gate material with varying work function aids in increasing the ON current by varying the barrier in the channel which in turn reduces the OFF current newline newline