Electromechanical Coupling Response Characteristics Of MCT High Voltage Switch Under Static/Dynamic Loads

As a typical representative of high-power MOS control semiconductor devices,MCT high-voltage switch is selected as the core device of the next generation of ground penetrating weapon intelligent fuze initiator because it can use conventional MOS gate-controlled signal to control the switch conduction,and the pulse peak current can reach thousands of amperes in a hundred nanoseconds,and the positive blocking voltage can reach thousands of volts.However,at present,the research on the working characteristics of MCT in the extremely complex multi-physics coupling environment of ground penetrating weapon is not sufficient.In this paper,the electromechanical coupling response characteristics of MCT under complex extreme environment are studied by means of experimental research,numerical simulation and theoretical analysis.The electromechanical coupling response characteristics and failure mechanism of MCT high voltage switch under static/dynamic load are revealed from macro and micro levels respectively.The main work and research results of this paper are as follows:（1）The electrical parameters of MCT high voltage switch under different constant overload are collected by using universal testing machine to simulate the constant overload environment.The rise time,fall time,turn-on loss and impedance change of MCT discharge current are analyzed.The experimental results show that with the increase of MCT strain,the rise time of discharge current decreases from 0.08 ms to0.03ms,and it is 0.04ms after unloading.There was no significant change in the falling time;the turn-on loss increases by up to 30%,from 0.20k W to 0.26k W.The total resistance in the channel decreased from 833.30Ωto 564.22Ω.（2）The Split Hopkinson Pressure Bar（SHPB）experimental device was used to simulate the strong dynamic load environment.The bullets were applied to the MCT at the speeds of 4.50m/s,7.31m/s,7.67m/s,10.04m/s,12.6m/s,10.12m/s and 25.61m/s,respectively.The experimental parameters before,during,after and 5minutes after the impact were collected.The experimental results show that when the overall strain of MCT is less than or equal to 0.026 and the peak stress is less than or equal to10.55MPa,the function of the device will not be affected.When the overall strain of MCT is in the range of 0.045～0.046,the peak stress is in the range of 41.70～46.70MPa,the function can be restored to damage,and the MCT function will return to normal after standing for 5minutes.The overall strain is in the range of 0.046～0.052,the peak stress is in the range of 51.98～53.48MPa,and the function can not be restored.（3）Based on the electromechanical coupling response experiment of MCT under static/dynamic loads,combined with COMSOL Multiphysics and Abaqus/CAE finite element software,the numerical simulation of MCT under corresponding experimental conditions was carried out.The accuracy of numerical simulation was verified by DIC technology and one-dimensional stress wave propagation theory.The principle and evolution of functional damage of MCT under different mechanical loads were analyzed.The numerical simulation results show that the stress concentration occurs at the edge of monocrystalline silicon in MCT under constant load,the peak stress range is 25.5-134.0MPa,and the maximum strain range is 7.41×10^-3-0.199.Under the impact load,because of the gap between the oxide layer and the gate contact interface,the device produces functional recoverable damage.Due to the crack extension of monocrystalline silicon under the impact load,the device produces functional irreparable damage.（4）Based on the numerical simulation results of MCT under the corresponding experimental conditions,the changes of conduction band and valence band structure of single crystal silicon under[110]/（001）uniaxial stress are studied.Based on the Schr?dinger equation,the potential energy operator is established.Based on the k·p perturbation method,the E（k）-k model near the minimum value of conduction band of single crystal silicon is established by introducing strain Hamiltonian Hε,ν,and the conduction band structure of single crystal silicon under uniaxial strain is analyzed.Combined with the physical field interface of’Schr?dinger equation’in COMSOL Multiphysics,the valence band structure of monocrystalline silicon under uniaxial strain was analyzed by k·p perturbation method based on strain Hamiltonian perturbation.