本論文探討利用超音波霧化熱裂解法沉積氧化鋁於非平面式之金氧半電容。透過實驗發現，超音波霧化熱裂解法有非常良好的包覆及填洞能力，因此非常適合應用於非平面式結構的介電層。為了瞭解超音波霧化熱裂解法沉積之氧化鋁的組成，在本論文中使用了穿透式電子顯微鏡、原子力顯微鏡及化學分析電子儀來進行量測和探討。從穿透式電子顯微鏡拍出的圖可以看到，超音波霧化熱裂解法成長的氧化鋁薄膜非常均勻且完整的包覆矽通道。另外，在膜厚控制上超音波霧化熱裂解法也相當精準，氧化鋁沉積速率大約每分鐘3.5奈米，氧化鋁薄膜大約20nm。在原子力顯微鏡量測中，可以發現氧化鋁薄膜相當平整，其方均根(RMS)值約為0.75nm。更進一步，利用化學分析電子儀量測發現，利用超音波霧化熱裂解法沉積的氧化鋁之鋁和氧的比例約為2比3，表示其氧化鋁薄膜有很好的品質。在瞭解薄膜之材料分析之後，接著進行電容-電壓(C-V)及電流-電壓(I-V)之電性分析。從C-V曲線中，可以計算出等效氧化層厚度(EOT)和實際氧化層厚度(t_ox)。發現t_ox和穿透式電子顯微鏡量出的厚度非常接近。接著，由I-V曲線可以計算出閘極電流密度。和其他不同的介電層製程比較，從外插法得到的趨勢線可以看出使用超音波霧化熱裂解法沉積的氧化鋁薄膜在較小的EOT情況下也能有很好的抑制漏電的能力。因此超音波霧化熱裂解法有應用於非平面式結構之介電層的潛力。

This research proposes the characterization of aluminum oxide (Al2O3) deposition by ultrasonic spray pyrolysis (USP) technique for non-planar MOS capacitor. We found that the Al2O3 thin film deposited by USPD is very suitable as the dielectric layer of non-planar structure due to the excellent hole-filling and coverage ability.In order to analyze the oxide layer composition, we utilized the transmission electron microscopy (TEM), atomic force microscopy (AFM) and electron spectroscopy for chemical analysis (ESCA) in this research. First, from the TEM images, we found that the Al2O3 thin film is fully wrapped around the Si channel, and the uniformity of Al2O3 is very good. Furthermore, the deposition rate of Al2O3 deposited by USPD is about 3.5nm per minute. The USPD method showed good thickness controllability for dielectric process. From AFM images, we observed that the surface of Al2O3 deposited by USPD is quite smooth. The root mean square (RMS) of USPD case is just 0.75nm. Moreover, we certified the composition of Al2O3 by ESCA. We found that the aluminum/oxygen ratio is about 2 : 3. It indicate the high quality of Al2O3 deposited by USPD.
After material analysis, we executed the capacitance-voltage (C-V) and current-voltage (I-V) electrical characteristics analysis of our devices. We calculated the equivalent oxide thickness (EOT) and oxide thickness (t_ox) by capacitance value. We found that the calculated t_ox is quite similar to the oxide thickness measured from TEM. Then, we calculated the gate current density of our devices and compared to others dielectric layer process. The tendency of extrapolation line of USPD case shows good gate leakage immunity in small EOT. Therefore, the ultrasonic spray pyrolysis technique is suitable for the dielectric layer of non-planar structure.

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