分体圆柱谐振腔法用于金刚石膜微波介电性能测试的研究

针对金刚石膜微波介电损耗低、厚度薄带来的微波介电性能测试难点, 研制了一台分体圆柱谐振腔式微波介电性能测试装置。利用不同直径的蓝宝石单晶样品, 用上述装置对低损耗薄膜类样品微波介电性能的测试能力及样品直径对测试结果的影响进行了实验研究。在此基础上, 使用分体圆柱谐振腔式微波介电性能测试装置对微波等离子体化学气相沉积法和直流电弧等离子体喷射法制备的高品质金刚石膜在Ka波段的微波介电性能进行了测试比较。测试结果表明, 由Raman光谱、紫外-可见光谱等分析证明品质较优的微波等离子体化学气相沉积法制备的金刚石膜具有更高的微波介电性能, 其相对介电常数和微波介电损耗值均低于直流电弧等离子体喷射法制备的金刚石膜。

Measurement of Microwave Dielectric Properties of Diamond Films Using Split-cylinder Resonator Method

Regarding to the difficulties in measuring microwave dielectric properties of diamond films due to their characteristics of low dielectric loss and small thickness, a split-cylinder resonator apparatus was established. By measuring dielectric performances of sapphire samples with different diameters, the capability of the split-cylinder resonator for measuring low dielectric loss materials was demonstrated, and the influence of sample’s diameter on measurement results was studied. Then by using the split-cylinder resonator apparatus, dielectric properties of high quality diamond films prepared by two different methods, microwave plasma chemical vapor deposition (MPCVD) and DC arc plasma jet, were measured in the Ka band. Results show that the diamond film deposited by MPCVD method has a higher quality than that of the diamond film deposited by the DC arc plasma jet method, which is consistent with the results of their Raman and UV-visible absorption spectra. The results indicate that both the relative dielectric constant and the loss tangent of the sample deposited by MPCVD method are lower than those of the sample prepared by DC arc plasma jet method.