金屬(Al)/氧化鋯(ZrO2)及氧化釤(Sm2O3)/矽(Si)薄膜電容器與場效電晶體之製作與電性分析

何曉碩(Hsiao-Shuo Ho)

指導教授 ： 李雅明

國立清華大學/電機資訊學院/電子工程研究所/碩士(2007年)

https://doi.org/10.6843/NTHU.2007.00208

摘要

本實驗中，我們使用射頻磁控濺鍍法沈積氧化鋯(ZrO2)和氧化釤(Sm2O3)薄膜，成功地製作了金屬（Al）/氧化鋯（ZrO2）與氧化釤(Sm2O3)/半導體（p-Si）結構的電容器與電晶體。我們另外製作金屬（Al）/二氧化矽（SiO2）/半導體（p-Si）結構的電晶體來當作參考。
我們以split C-V的量測方式，來萃取有效載子移動率(effective mobility)，得到ZrO2電晶體最大有效載子移動率為211 cm2/V-s，Sm2O3電晶體最大有效載子移動率為238 cm2/V-s。再經由變溫實驗(11~300K)，得到N通道的閘極場效電晶體有效通道電子移動率的衰減機制與臨限電壓 (threshold voltage, VTH) 的漂移狀況與溫度的變化，來探討載子遷移率衰退機制分析。
實驗結果發現，ZrO2電晶體比SiO2電晶體受到更嚴重的庫侖散射，很有可能是因為有較多的oxide trapped charges存在於ZrO2所造成。Sm2O3電晶體比SiO2電晶體受到更嚴重的聲子散射，很有可能是因為high-k薄膜的軟性光學聲子所造成。

關鍵字

高介電材料 ； 電晶體 ； 電容器 ； 氧化鋯 ； 氧化釤 ； 電子遷移率

並列摘要

Metal-oxide-semiconductor (MOS) capacitors and n-channel metal-oxide-semiconductor-field-effect-transistors (MOSFETs) with ZrO2 and Sm2O3 gate dielectrics were fabricated. The mobility degradation mechanisms of ZrO2 and Sm2O3-gated transistors were studied in the temperature range from 11K to 300K. N-MOSFETs with SiO2 gate dielectric was used as the reference. The effective electron mobility was measured by the split C-V method. The electron mobility of n-MOSFETs with ZrO2 and Sm2O3 gate dielectrics are 211 and 238 cm2/V-s, respectively. The variation of the threshold voltage and the electron mobility as a function of temperature was characterized. Comparing with SiO2-gated transistors, the electron mobility of ZrO2-gated n-MOSFETs is limited by additional Coulomb scattering at electric field above 0.33 MV/cm. The reason is most likely due to higher density of oxide trapped charges in the ZrO2 layer. Comparing with SiO2- gated transistors, the electron mobility of Sm2O3-gated n-MOSFETs is limited by additional phonon scattering at electric field above 0.22 MV/cm. The reason is most likely due to soft optical phonons in Sm2O3-gated n-MOSFETs.

並列關鍵字

high-k ； MOSFET ； MIS ； ZrO2 ； Sm2O3 ； mobility

參考文獻

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