硅表面清洗对7nm热SiO_2栅介质可靠性的影响

Dependence of 7nm Gate Oxide Reliability on Silicon Surface Cleaning Approach

实验研究了硅表面清洗方式对７ｎｍ 热氧化ＳｉＯ２ 栅介质可靠性的影响．结果表明，稀ＨＦ酸漂洗后ＲＣＡ 清洗时降低ＳＣ１（ＮＨ４ＯＨ／Ｈ２Ｏ２／Ｈ２Ｏ）温度对提高栅介质可靠性有利，但仍不如用ＳＣ２（ＨＣｌ／Ｈ２Ｏ２／Ｈ２Ｏ）或Ｈ２ＳＯ４／Ｈ２Ｏ２ 清洗效果好．稀ＨＦ酸漂洗后用Ｈ２ＳＯ４／Ｈ２Ｏ２ 清洗得到的栅介质不仅表现出优良的击穿电场分布特性和击穿电荷分布特性。

We have studied the effects of silicon surface cleaning on the reliability of 7nm gate oxides.It is shown that,although RCA cleaning with lower SC1 temperature can improve the gate oxide integrity,chemical preoxide formation in SPM solution prior to gate oxidation is much more effective.The oxide with SPM preoxide also exhibits higher integrity than that with chemical preoxide formed in SC2 solution.In addition,it is demonstrated that fewer Si/SiO\-2 interface states and trapped holes are generated by hot\|carrier injection in the oxide with SPM preoxide compared to the RCA cleaned oxide.