Study On The Response Characteristics Of Alpha Particles In GaN/AlGaN Structure PIN Based Detectors

The GaN materials as the representative of the third generation wide band gap semiconductor material with the advantages of high pressure resistance, high temperature resistance and high resistance to radiation,these excellent properties make it able to be applied to the field of nuclear radiation detectors. The use of wide band gap semiconductor materials to design a new type of structure has a positive role in promoting the development of semiconductor devices.A new type of PIN nuclear radiation detector is designed by using the structure in the new heterojunction GaN/AlxGa1-x N structure in this paper. The working principle of AlxGa1-x N based nuclear radiation detector with linear variable component is analyzed theoretically,The structure parameters of the detector are calculated from the theoretical calculation and the Visual-TCAD simulation software is used to construct the device structure and carry out electricity and alpha particle simulation,electrical properties of the detector are analyzed in detail from the aspects of positive and negative I-V characteristics,potential structure and carrier distribution,the particle simulation results show that the thickness and the doping concentration of the window layer and the depletion layer are most affected by the particle characteristics. Based on the theoretical design value of alpha particle simulation, we mainly study the characteristics of Alpha particles in the detector.using the alpha particle is the most commonly used incident energy 5.486 Mev multiple sets of data simulation of pin detector three zone thickness and doping concentration one by one to tell time, energy deposition rate and charge collection capabilities of three performance is a comprehensive analysis of the index finally comes to the conclusion that theory to design the optimal value,the optimal thickness value of P-I-N is 0.2μm-10μm-5μm, P and N region doped optimal value 1018cm-3 and 1019cm-3, I region doping concentration is 1013cm-3, analysis of the thickness of each layer, the doping concentration of the specific impact of three performance metrics.For the optimized structure of detector on the effects of different temperature, different bias and different radiation source on performance,and put forward the theory that energy deposition rate and charge collection rate of the detector are raised by using the high energy radiation source with a reasonable increase of the depletion region..The results show that for resolving time detection of alpha particle nature common 3-8 Mev2.65×10-11s-5.71×10-11 s, 3-6 Mev alpha particle energy deposition rate reaches more than98%, for the beta particles below 100 Kev energy, the resolution time is2.1×10-11s-6.02×10-11 s, the energy deposition rate reached 100%.We get the design scheme of the ohmic contact alloy in the preparation of the nuclear radiation detector and the parameters of the annealing process were obtained through the experiment.