| For the time being,the measurement of the real-time temperature and aerodynamic parameters for the geothermal and well oil offshore drilling has raised higher requirements for the semiconductor devices used in the measurement system,including the materials,structure design,package configuration and so on.The semiconductor devices are required to be capable of keeping well working performance in harsh environments,like high temperature.Traditional silicon-based devices have a wide range of applications,while the concentration of the current carrier rises rapidly in high temperature above 300°C,which prevents it from exerting its semiconductor performance.The SiC based semiconductor devices that developed subsequently can withstand higher temperature,but it needs to be integrated with substrate in some applications,like ceramics.There have been reports from abroad.Ceramic are widely used in high temperature and have a promising development prospect,while there are no reports on ceramic based semiconductor devices in domestic.Aiming at the above-mentioned applicable requirements,a thin-film alumina based a-IGZO?amorphous-Indium gallium zinc oxide?schottky barrier diode?SBDs?is proposed.And the J-V characteristics in 21°C and the high temperature sensing properties are analyzed and verified,providing new ideas for the follow-up research on the ceramic based semiconductor devices and the integration on the high temperature sensors.The main research contents and the results of this article are as follows:1.Taking N-type semiconductor for example,the formation conditions of ideal metal-semiconductor schottky contact barrier and the expressions for relative parameters and properties?current transmission mechanism and space depletion layer capacitance?are analyzed;and the key factors that affect the barrier height in practice are discussed,including the surface state and the image force;two cases of the ohm contact are analyzed,i.e.the work function difference between the metal and semiconductor and the quantum tunneling effect caused by high concentration doping.Through the analysis of the contact of schottky and ohm,the equivalent circuit model of SBDs with vertical structure is proposed and designed.2.The SBDs are prepared on the Al2O3 substrate with MEMS technology?including electron beam evaporation,sputtering,etc.?,and the J-V the characteristic of SBDs fabricated under different preparation parameters are tested with the Keithley 4200A-SCS analyzer and the Cascade probe station.By comparison with J-V curves of different SBDs that are fabricated with different parameters,i.e.the anode metal,thickness of the a-IGZO layer,area of the diode rectifier junction and the sputtering oxygen content,the impacts are analyzed and optimized.3.The SBDs that fabricated with optimized conditions are tested with Lakeshore Model CRX-6.5K in 21-400°C.Through the I-V curves,it is concluded that when the voltage of-11V is applied,the forward opening voltage of the SBDs decreases with the increased temperature,and they are approximately linear with temperature;when the temperature increases,the I-V characteristic curve shifts from right to left;When the temperature rises from 21oC to 400oC,the forward opening voltage of the SBDs is reduced from 0.64 V to 0.14 V,and the average voltage drift rate is 1.32 mV/oC;the opening resistance decreases from 3.81 k?to 1.54 k?,and the average drift rate is 5.99?/°C.According to the J-V curves,the ideal factor n decreases with the increased temperature,while the contact barrier?Bn is increased.4.Additionally,the SBDs are considered as temperature sensors in order to explore the application prospect of them in high temperature.It is concluded that the sensitivity is 0.81mV/oC with forward current density of 10-5 A/cm2,1.37 mV/oC with 10-4 A/cm2,and 1.59mV/oC with 10-3 A/cm2.It is seen that the the sensitivity of the sensor increases with the increase of forward current density,but the linearity decreases with the increase of temperature. |
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