Optimization of gate oxide N/sub 2/O anneal for CMOSFET's at room and cryogenic temperatures
Optimization of gate oxide N/sub 2/O anneal for CMOSFET's at room and cryogenic temperatures
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室温和低温下 CMOSFET 栅极氧化物 N/sub 2/O 退火的优化
DOI：
10.1109/16.297731
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发表时间：
1994
影响因子：
3.1
通讯作者：
P. Ko
中科院分区：
文献类型：
--
作者：
Zhi;Zhi Liu;J. Krick;H. Huang;Y. Cheng;C. Hu;P. Ko
本文研究了栅极氧化物N/sub /O退火对CMOSFET在300 K和85 K下的特性、器件可靠性和逆变器速度的影响。研究了两种氧化层厚度（60和110 /spl Aring/）和五种N/sub /O退火条件（900/spl sim/950/spl℃，5/spl sim/40 min）以及非氮化工艺和通道长度（0.2 ~ 2/ spl mu/m），以建立Si/SiO/sub / 2/界面氮浓度与所制器件相对性能之间的相关性。我们的结论是，一个简单的氧化后N/sub 2/O退火步骤可以使CMOSFET的寿命增加4/spl sim/10倍，有效抑制P- mosfet的P/sup +/多晶硅栅极的硼渗透，而不会牺牲CMOS逆变器速度。我们还发现，在低温下，界面硬度和电荷捕获特性的改善仍然存在。所有这些改进都与Si/SiO/sub - 2/界面处的氮浓度密切相关。最佳的N/sub - 2/O退火发生在Si/SiO/sub - 2/界面处氮掺入量为2%左右，这可以通过在950/spl℃下退火5分钟或900/spl℃下退火20分钟来实现
This paper presents a study of the impact of gate-oxide N/sub 2/O anneal on CMOSFET's characteristics, device reliability and inverter speed at 300 K and 85 K. Two oxide thicknesses (60 and 110 /spl Aring/) and five N/sub 2/O anneal conditions (900/spl sim/950/spl deg/C, 5/spl sim/40 min) plus nonnitrided process and channel lengths from 0.2 to 2 /spl mu/m were studied to establish the correlation between the nitrogen concentration at Si/SiO/sub 2/ interface and the relative merits of the resultant devices. We concluded that one simple post-oxidation N/sub 2/O anneal step can increase CMOSFET's lifetime by 4/spl sim/10 times, effectively suppress boron penetration from the P/sup +/ poly-Si gate of P-MOSFET's without sacrificing CMOS inverter speed. We also found that the benefits in terms of the improved interface hardness and charge trapping characteristic still exist at cryogenic temperature. All these improvements are found to be closely correlated to the nitrogen concentration incorporated at the Si/SiO/sub 2/ interface. The optimal N/sub 2/O anneal occurs somewhere at around 2% of nitrogen incorporation at Si/SiO/sub 2/ interface which can be realized by annealing 60/spl sim/110 /spl Aring/ oxides at 950/spl deg/C for 5 min or 900/spl deg/C for 20 min. >