PI/TiO2 複合薄膜之合成與物性化性之分析研究及微波被動元件製作

Abstract

摘要 本論文為利用溶膠-凝膠法製備PI/TiO2複合薄膜，並對薄膜化學性質與物理性質作一探討分析。在化學性質方面，發現TiO2結晶比例會隨著氣氛中氧分量的增加而增加，而隨著TiO2的添加，PI薄膜的熱性質越差。在物理性質方面，將PI/TiO2薄膜製作成MIM結構，以分析低頻電性。探討在不同摻雜量以及不同熱處理條件對電性之影響。發現薄膜在300℃熱處理就會有結晶產生，而熱處理氣氛的氧含量增加，介電常數會隨之增加。薄膜中TiO2含量40wt%時有最大介電常數、介電損失與漏電流。 將商用PI薄膜與此介電薄膜分別做成微波濾波器，量測其高頻下之S參數，與Sonnet模擬比對，發現共振頻率負偏移，其原因為商用PI薄膜實際厚度小於設計厚度所致。PI/TiO2複合薄膜做成之微波濾波元件，則因薄膜在製程中受到破壞，導致電極短路而失效。

Abstract PI/TiO2 hybrid films have been fabricated by Sol-gel Process. The thermal property was going down with TiO2 doping increased. However, the ratio of TiO2 crystallization went up with oxygen atmosphere increased. The film has been sandwiched by Cr and Pt as the top and bottom electrode to study its electrical properties. The relationships among doping concentration, curing temperature, curing atmosphere, leakage current and dielectric constant was discussed. The highest dielectric constant would be obtained when the film of TiO2 doping concentration up to 40wt%. The films were crystallized at 300oC and its dielectric constant increased with oxygen atmosphere increased. The S parameters of microwave filter fabricated by the commercial PI and dielectric film was measured. Then, the result of commercial PI was compared with Sonnet simulation, the preset films’ thickness was less than simulated one. Then, the negative discrepancy between the experimental central resonant frequency and the simulated one is found. Microwave filter fabricated by the dielectric film was failed because of the film were destroyed and electrode were short.