Study Of Ion Energy Distribution Measurements

With the development of industrial technology, ion source has been widely used in ion beam etching of microfabrication, ion implantation of the surface modification of materials and the ion-beam assisted deposition of optical films preparation, therefore, accurately control of the ion beam energy is an important technical indicator for acquire precision machining and high-quality optical film.The development, measurement and stability of the ion energy analyzer is the primary assignment in this paper. First of all, according to the basic characteristics of the plasma, electrostatic theory deduced grid spacing of the ion energy analyzer. Secondly, use Simion electrostatic lens simulation software to calculate the effect of different grid parameters on the ion energy analyzer test results, with determine geometric parameters design and processing the ion energy analyzer, and written the interface procedures for data processing by Matlab. Finally, use developed ion energy analyzer test the ion energy distribution of broad beam cold cathode ion source and to analyze the stability of it. The results are as follow:1. Through the theory of plasma, electrostatic, derive the relationship between the plasma sheath thickness S and the Debye length λD, in the light of λD can define the thickness of the plasma sheath; according to the relationship between the sheath thickness and the grid spacing sheath, theoretically calculated out of the grid spacing of the ion energy analyzer.2. Applying the electrostatic lens simulation software of Simion to simulate the grid spacing, the size of the grid and filament diameter of the ion energy analyzer, the simulation results show that, when design ion energy analyzer different grid parameters have effect on the result of test, the transmittance of first grid is smaller than others, this is benefit for the plasma Debye length which fly in the ion energy analyzer, and increase the mesh grid size of others, in order to improve the accuracy of the testing result.3. With the developed energy analyzer to measure the ion energy distribution of broad beam cold cathode ion source, the results show that there are differences for ion energy distribution of broad beam cold cathode ion source in different working conditions, and the extraction voltage is greater, the ion energy which emission is larger. Then compared the ion energy of cold cathode ion source are measured by ion energy analyzer with the theoretical value, the average ion energy test error is less than2%,and the ion energy analyzer keep higher work stability when test every30minutes.