Thermal Performance Study Of GeTe Thin-film Phase Change Switches

Phase change switch is an electronic switch based on phase change materials.The resistance of phase change materials varies greatly before and after phase change,and the phase change switch made from this performance is used to achieve the switching function of the circuit.Phase change switches have excellent characteristics such as fast switching,low power consumption,reconfigurability,and non-volatility,and have good and widespread application prospects in electronic devices,communication technology,energy management,and other fields.Developing phase change switches may make electronic systems more efficient,reliable,energy-saving,and portable.This thesis aims to optimize the switching speed of GeTe phase change switches,and designs an indirectly heated GeTe thin film phase change switch with a groove on the back.The preparation and performance testing of the phase change switch have been completed.By using the Multiphysics simulation software COMSOL,the phase change switch structure is simulated and designed.Optimize the heat dissipation ability of the GeTe thin film phase change switch by digging holes and grooves on the back.The simulation results show that under the same pulse voltage,the time for the local average temperature of the phase change material region to reach the melting point(32.51 ns)is lower than that of the traditional structure(40.85 ns).Compared with traditional indirectly heated phase change switches,the amorphization time has been reduced by more than 45%.This proves that the design in this thesis greatly improves the heat transfer efficiency of phase change switches.We have studied the cooling process of amorphous phase change switches and demonstrated that the deep groove on the back of the phase change switch designed in this thesis can effectively propagate most of the heat in the vertical direction through heat conduction,with good heat dissipation performance,reducing the risk of burning out and incomplete crystallization of the phase change layer film,and improving the switching speed of the switch.Optimize the preparation of GeTe thin films by radio frequency magnetron sputtering.The process parameters for preparing GeTe thin films are optimized,achieving a resistance ratio of over 10~6 for amorphous/crystalline GeTe thin films.After annealing at 400℃,the GeTe thin film transformed from amorphous to crystalline,and the degree of disorder in the transition from amorphous to crystalline decreased.The device is prepared and the electrical properties of GeTe thin films are tested.The four-port GeTe thin-film indirect heating type phase change switch of the structure in this thesis is prepared,and its electrical and microwave properties are tested.The off-pulse voltage of the switch is 27 V,and the on-pulse voltage is 9 V.At 0-20 GHz,the isolation is greater than 30 d B and the insertion loss is less than 3.5 d B.The structure designed in this thesis has a closing time of approximately 550 ns and an opening time of approximately 3μs.The traditional structure phase change switch has an off-time of approximately 690 ns and an on-time of approximately 5.7μs.Compared to traditional structures,the total time is reduced by more than 40%and the number of cycles for phase change switches is also increased.