TCAD ANALYSIS OF HOT CARRIER RELIABILITY AND THERMAL BEHAVIOUR OF TRANSPARENT GATE RECESSED CHANNEL MOSFET

Abstract

In this thesis, a novel device structure called Transparent Gate Recessed Channel MOSFET (TGRC-MOSFET) is proposed to alleviate the hot carrier effects for the advanced nanometer process. TGRC-MOSFET involving a recessed channel and incorporates Indium Tin Oxide as a transparent gate. TCAD analysis shows that performance of TGRC-MOSFET surpasses Conventional Recessed Channel (CRC)-MOSFET in terms of high ION/IOFF ratio and better carrier transport efficiency in compare to Conventional Recessed Channel (CRC) MOSFET. This simulation divulges the reduction in hot-carrier-effects metrics like electron velocity, electron temperature, potential, and electron mobility. All the simulations have been done using DEVEDIT-3D and ATLAS device simulator. The work proposes the novel design for reduction in hot carrier and low power switching application. Ajay Kumar iv In thermal analysis of a novel design Transparent Gate Recessed Channel MOSFET (TGRCMOSFET) at 300K. TGRC- MOSFET involves a recessed channel and incorporates Indium Tin Oxide as a transparent gate. Simulation results show that performance of TGRCMOSFET surpasses Conventional Recessed Channel (CRC)-MOSFET in terms of heat capacity, heat conductivity, lattice temperature and total heat power in comparison to CRCMOSFET. All the simulations have been done using DEVEDIT-3D AND ATLAS device simulator. Indium tin oxide (ITO or tin-doped indium oxide) is a solid solution of indium oxide (In2O3) and tin oxide (SnO2). It is transparent and colourless in thin layers. Because of its two key properties, i.e. electrical conductivity and optical transparency, indium tin oxide is used as one of the most widely used transparent conducting oxides. Also, the In2O3 phase itself contributes free electron for electrical conductivity. Furthermore, with the reduction in transistor size, intrinsic self-heating effects have become unfavourable in low power applications. As the issue of heat becomes increasingly important in sub-micron MOSFETs, it becomes increasingly more important to accurately measure and model its thermal parameters to fully characterize its thermal performance. High heat capacity of TGRC-MOSFET device is favourable for high power applications as compared to CRC MOSFET. Furthermore, low thermal conductivity of a device, finding application as heat insulation. TGRC-MOSFET has lower thermal conductivity as shown in fig. 3. In addition, there is reduction in hot electron (HE) injection gate current and impact ionization (II) substrate current in TGRC-MOSFET compared to CRC MOSFET which improves the device speed performance and hence reduced the power dissipation as it is evident from results respectively. Since, there is appreciable reduction in electric field at the drain side in TGRC-MOSFET in comparison to CRC-MOSFET which results in lower leakage current. The noise assessment of Novel Transparent Gate Recessed Channel MOSFET has been investigated based on the simulated result from ATLAS device simulation. TCAD simulation results show TGRC-MOSFET divulges Conventional Recessed Channel (CRC)- MOSFET in terms of reduction in noise figure, noise conductance and parasitic capacitances. It also achieves higher optimum source impedance for high performance applications where noise immunity is a key factor. Here we accentuate our focus on Transparent Gate architecture incorporation onto the Conventional Recessed Channel MOSFET for superior noise performance of scaled MOS devices. Intensive TCAD device simulations have been performed to probe the internal transport conditions of CRC MOSFET and TGRC-MOSFET, Ajay Kumar v and substantial interpretation is given to the internal behaviours observed in all the devices investigated. TCAD simulation reveals the deterioration in minimum noise figure, noise conductance and parasitic capacitances. It also achieves higher optimum source impedance. This work presents a TGRC-MOSFET device which is reliable for RF applications and CMOS technology for the designing of multi-gigahertz communication circuits.