Simulation And Analysis Of Temperature Characteristics Of Metal/n-ZnO Schottky Diode Based On N-Si Substrate

In view of the problems in the fields of geothermal and thermal power generation,petrochemical industry,automobile industry,aerospace,metallurgy and other high temperature fields,such as narrow range of temperature measurement,insensitive temperature measurement and difficult real-time temperature measurement,how to realize high sensitivity real-time high temperature measurement in the field of extreme high temperature and linear output in a wide temperature range has become the focus of research.The problems of temperature measurement in the field of high temperature include:the narrow range of high temperature measurement for steam boilers and control circuit devices in thermal and geothermal power plants,the difficulty of real-time temperature measurement for equipment such as wind furnaces and pipes in steel mills,and the insensitivity of temperature measurement for overheating protection circuits of locomotive engines and their cylinders.In order to solve these problems,there is an urgent need for a temperature sensor which can be applied to high temperature conditions and has the function of wide temperature range and high sensitivity real-time temperature measurement.This thesis designs and simulates a metal/n-Zn O Schottky diode based on n-Si substrate using COMSOL Multiphysics software.The current density-voltage(J-V)characteristics of diodes with different parameters(metal,n-Zn O film thickness and doping concentration)were simulated and analyzed at room temperature(298 K)and high temperature(523 K?873 K).The final results show that the Schottky diode is not only suitable for high temperature(523 K?873K)environment,but also realizes the linear output of high sensitivity real-time measurement of high temperature(523 K?873 K)and wide temperature(350 K)range.This has opened up a new idea for the research of high temperature semiconductor devices with wide temperature range and high sensitivity real-time temperature measurement.The main contents and results of this thesis are as follows:This thesis first introduces the development of Schottky diode temperature sensor,and also discusses the advantages and disadvantages of sensors with different structures.Following the example of N type semiconductor,the basic principle of Schottky diode is introduced,and the Schottky contact,current transmission mechanism,effect of surface state and mirror force on barrier height and ohmic contact are explained by using metal-semiconductor contact theory,these contents lay a theoretical foundation for the design of schottky diodes based on metal/n-Zn O/n-Si structure.Secondly,it introduces the advantages of n-Zn O semiconductor materials,the metal materials selected by diodes,the design and simulation of metal/n-Zn O/n-Si Schottky diodes using COMSOL Multiphysics software.The J-V characteristics of diodes with different parameters(metal,n-Zn O film thickness and doping concentration)under normal temperature are simulated and analyzed.Having obtained the influence of the above parameters on its J-V characteristics,and finally the optimal structure of the diode.The diode structure with low current density at room temperature is selected for high temperature detection,so the relative temperature becomes the main factor affecting the current density.Therefore,for the diodes with Cu?Ni?Pt/n-Zn O/n-Si three structures,the Zn O film thickness is 120 nm?220nm?220nm;and the doping concentration is 10¹⁰/cm~3,respectively for high temperature sensing.Third,the current density-voltage characteristic test of Schottky diode based on metal/n-Zn O/n-Si structure at high temperature(523 K?873 K)is completed.The results show that if the applied bias voltage range is-1 V?1 V,the forward opening voltage of the diode decreases gradually with the increase of temperature from 523 K to 873 K,and the opening voltage and temperature at different temperatures are approximately linear;as the temperature rises,the J-V characteristic curve shifts from right to left.Under high temperature,the effect of temperature on current density is more significant than that of bias voltage.Compared with forward bias,the current density at different temperatures is more obvious when loading reverse bias.Lastly,according to the calculation results,the diode with Pt/n-Zn O/n-Si structure is selected for high temperature(523 K?873 K)sensing when loading forward bias,at this point the diode also has good rectification characteristics.The temperature detection range of the diode is large(350 K),the response sensitivity is 1.32 m V/K,the fitting degree of bias voltage and temperature is 0.998,and the power consumption is 35 n W?0.21?W.When reverse bias is loaded,Cu/n-Zn O/n-Si diodes are selected for high temperature(523 K?873 K)detection.The temperature detection range of diode is large(350 K),the response sensitivity is 6.35?A/K,the fitting degree of current density and temperature is 0.986,and the power consumption is 8.34?W?1.16 m W.For ordinary temperature sensors,the maximum temperature detected is 673 K,the sensor has higher temperature measurement(873 K),wider real-time temperature measurement range(350 K),higher sensitivity,significantly enhanced correlation with temperature,low energy consumption,small size,low cost,short response time and stable performance.The sensor solves the problems of narrow temperature detection range,insensitive to large temperature fluctuation and difficult to measure high temperature in real time.It will also have broad development space and application prospect in the field of micro-nano-high temperature sensing.