以溶凝膠法製備五氧化二鉭薄膜

Abstract

本實驗以溶凝膠法(Sol-Gel Method)與旋塗法製備五氧化二鉭薄膜並研究 其經熱處理後的化學組成、結構與電氣特性。X-光與歐傑電子能譜儀的分 析顯示所製成薄膜之化學計量比非常接近理想的數值。經400℃，4小時熱 處理的薄膜具有最高的介電常數(24.47)與最佳的崩潰電壓(1.23MV/cm)， 但微觀結構的分析顯示以溶凝膠法製成的五氧化二鉭薄膜中往往含有許多 微缺陷與孔洞，其電性亦因而受到限制。由於再結晶會產生更多的缺陷， 因此更進一步的熱處理對結構與電性均無助益。 In this work we studied the preparation, structure and properties of Ta2O5 films grown by sol-gel method. The specimems were prepared byspin-coating the starting solution containing Ta(OC2H5)5 onto Si wafersfollowed by various heat treatments. X-ray and AES analyese indicted atthe film has [O]/ [Ta] ratio rather close to exact stoichiometry. The films annealed at 400℃for 4hrs exhibited the highest dielectric constant (24.27) and the best breakdown voltage (1.23MV/cm). However, as revealed by TEM, SEM and AFM characterizations, the Ta2O5 films prepared by sol-gelmethod contained many micro- defects and voids which severely restricted their electrical performance. Recrystallization during further annealsinduced even more defects in Ta2O5 films, which showed no benefication of both structure and electrical properties of the films.