Research On Transition Layer And Protective Layer Of Spindt-Type Field Emission Array

Due to its unique characteristics, such as cold emitting, better controllability, high current density, short corresponding time etc, Spindt-type field emission cathode has a broad application prospect. However, field emission array are easy to cause emission tips inhomogeneity or even tips loss, when prepare the FEA, which will severely limit the FEA’s application. In order to make FEA work stable and have a better performing,this paper adds resistance layer and transition layer in the traditional Spindt-type FEA,and use Lanthanum hexaboride(LaB6) as emitting layer.-Si layer uses as resistance layer mainly because it can play a role in limiting current and dividing voltage in the whole emitter. The thermal expansion coefficient of Mo is close to-Si and LaB6,which is good to improve the stability of the whole tips and play a role in reducing thermal stress. lanthanum hexaboride(LaB6) has a lot of advantages such as: low work function, physical and chemical stability, high current density and so on, so LaB6 can be used as emitting layer. The main research of this paper includes:Firstly, the paper analysis the influence of temperature fields and stress fields to Spindt-type FEA in different layer’s thickness through ANSYS software. According to the result of simulation, we can see that when the Spindt-type field emission exist transition layer, it can reduce thermal stress of emitting layer. And getting best simulation parameters, which are the thickness of resistance layer being 0.072μm, the thickness of Mo transition layer being 0.2μm, and the thickness of emitting layer being0.728μm.Secondly, using the result of simulation, I prepare-Si thin-film in different power and substrate temperature. And through SEM analysis, XRD analysis and electrical performance, we can get the best deposited thin-film parameters. The concrete parameters of-Si thin-film are evaporation power being 107 W, substrate temperature being 200℃.Thirdly, I prepare Mo thin-film in different power and substrate temperature. And through SEM analysis, XRD analysis and electrical performance, we can get the best deposited thin-film parameters. The concrete parameters of Mo thin-film are evaporation power being 312 W, substrate temperature being 200 ℃, deposited time being 20 min.Fourthly, I prepare compounded thin-film in the best parameters, and test theirs thermal stress. The result of test indicates that the max thermal stress of compounded thin-film appear in transition layer and make the stress of emitting layer reduce 1/3,which is about 9% comparing with the result of simulation.Fifthly, according to the micromachining techniques of semiconductor, we can prepare the Spindt-type field emission array and test their emission property. According to the result of compounded field emission, we can see that it is viable to add transition layer and resistance layer in FEA. After the burn-in test, the current of field emission can reach 5300μA. The emission current density is 0.5A/cm2.