Electric Properties And I-t Curve Research Of 3D Trench Electrode Si Detector With Adjustable Central Collection Electrode

Since silicon can react with many radiation’s including visible light,X-ray,high energy particle,it has fundamental advantages in the cost and applications as compared with other semiconductor materials.So silicon-based detectors have been widely applied in aerospace,medical,industrial detection,security detection,radiation monitoring,and high energy physic experiments.When silicon detector applied in severe radiated environment,especially high energy physic experiments application.As the key performance,radiation tolerant was widely concern.For silicon detector,radiation hardness was mainly focus on two directions:1doping special impurity into detector bulk;2.Design new detector structure.In this thesis,based on design of new detector structure,we research radiation hardness of silicon detector including:For radiation hardness research,we introduce details of displacement damage from micro mechanism to macro properties,that following:damage mechanism→non ionising energy loss→defects induced by displacement damage→the change of macro properties.And based on those,we research the performance of 3-D trench electrode Si detector with adjustable central collection electrode suffering severe radiation damage.Based on Possion equation,we proposed a new structure cell that can be depleted at same voltage in different regions.And those results have been compared to those obtained from the full 3D simulation using a 3D-TCAD tool;For research electrical properties of designed structure,in this paper,we investigate electric field and potential using TCAD tool.And finally,we obtain minimum length of central collection electrode and maximum electrode space suffering radiation damageΦ_eq=1x10¹66 n_eq/cm²;As the extension of the structure will amplify noise,we also studied the detector leakage current and its geometric capacitance,and obtained the relationship between the size of central electrode length and noise increase.Finally,the max volume has been given;For the study of detector charge collection effciency（CCE）suffering after high radiation damages in different regions of the detector,we have built a physic model and used the matlab tool to simulate.Simulation results are discussed.For research bottom effect of 3-D trench electrode Si detector,in this thesis,we build model of MIP（minimum ionizing particle）incident into detector arrays and studied electric field and weighting field with different depth of trench electrode.For exactly research on detector’s induced current and drift time（i-t curve）performance,based on finite element theory and 3-D distribution of electric field and weighting field,we build the new simulation method for MIP incident in silicon detector with 3-D electric field.And use matlab to simulate carriers drifting process.Based on the carrier drift model established in this paper,i-t curve induced by MIP with different trench depths is simulated.And we analyzed those results.