Modeling Of Logic Device Based On Spin Transfer Torque

In recent years,the characteristic size of traditional CMOS microelectronic devices has reached the order of ~ 10 nm,which is close to the diameter of the atom.This blocks the idea of increasing the monolithic integration according to Moore's law,so it is urgent to find a new technology to replace or surpass CMOS technology.Spintronic devices have become a strong candidate to replace CMOS technology because of their non-volatile and easy logical implement.Following the research method for microelectronic devices,we could first build up a device model to describe the physical characteristics of spintronic devices and then make it compatible with the existing circuit simulation and verification tools,so the new devices can gradually replace the old technology or eventually form a spin-CMOS hybrid circuit.Based on this idea,this paper provides a modeling method to study spin electronic devices,in order to make the research easierThe basement of the spintronic device is the magnetic part,for which,we first use the equivalent circuit method to model the device.By analyzing the basic characteristics of the device,we use the circuit element to simulate its characteristic,and then use the HSPICE platform to simulate the built model.However,there are some problems in using the basic circuit components to simulate the physical characteristics of the device.So we choose another mathematical method to describe the dynamic characteristics of the device strictly.The focus of thesis is the establishment of 3-D SPICE devices model using mathematical method to describe the physical behavior of particles in nanomagnetic devices,that is,the time-domain magnetization dynamics in magnetic thin-film spintronic devices.The precession equation of magnetic moment is transformed into the differential equation of correlation angle with effective field components within spherical coordinate system.Then the spin-conductance of the non-magnetic part and the interface part is deduced,and the completed model is connected by the spin-injection part and the spin-transfer part using the nodal analysis method.Finally,the mathematical model of the all-spin logic device is completed by combining the ferromagnetic part and the spin-conductance parts,and then we converted built mathematical model to SPICE model by Verilog-A language.The model we built has necessary I/O ports to facilitate interconnection with standard CMOS circuits for co-simulation and co-verification.And then we verified the static and dynamic characteristics of our device model with the simulation platform Cadence.Finally,the all-spin logic devices including non-gate,three-input NAND and NOR gate are constructed and verified based on our built model.