奈米級P型高介電/金屬閘極之金氧半電晶體製程最佳化與有效功函數調控的研究

為了維持互補型金氧半電晶體（CMOS）持續的微縮尺寸，高介電常數（High-k）介電層與金屬閘電極（Metal gate）技術已成為邏輯CMOS製程技術基礎。然而金屬閘電極的功函數受到材料本質特性限制極易受到傳統高溫回火影響而退化至矽能帶中間。因此金屬閘電極不佳的熱穩定性使得High-k/Metal gate技術無法滿足能帶邊金屬功函數（Band edge metal work function）的要求，特別是p-type MOSFET。本文研究利用回火，Al2O3介電層，以及Al或F離子植入來調控金屬閘極功函數以達到元件特性的需要。作者藉由結合Al以及F離子植入，成功的在前金屬閘極製程下實現能帶變金屬功函數，但也因此出現了些微漏電流增加的壞處。此外，等效氧化層厚度 (EOT) 也會受到前金屬閘極製程必經高溫製程步驟的影響，往下微縮的能力會受到限制。為了滿足未來元件的應用，引入了可以避免經過高溫製程步驟的後金屬閘極製程。從元件展現出的電性結果包含I/V，C/V以及EDS物性分析來驗證，後金屬閘極製程的確適用於p-type MOSFET能帶邊金屬功函數的需求。而且，藉由在O2氣體中後續回火，可以再更提升金屬功函數而不會增加漏電流以及增厚等效氧化層厚度。又藉由EDS分析金屬閘電極的剖面元素成分特徵，我們發現氧的含量控制了p型閘電極的金屬功函數。

關鍵字

高介電；金屬閘極；功函數

並列摘要

To sustain CMOS transistor continuously scaling, high-k and metal gate technology has become the foundation of logic CMOS technology. Because of the direct tunneling effect, a high gate leakage will be induced in the conventional Poly/SiON gate with a very thin SiON dielectric. Besides, the poly depletion effect also limits Tox_inv for further scaling. Furthermore, the p-type effect work function of a metal gate electrode is easily degraded to Si middle band gap after high temperature activation steps. To overcome the drawback, in this thesis, we study the use of post dielectric annealing, Al2O3 cap layer, F or Al implantation to modulate work functions of gate metals to meet the p-type MOSFET requirements. By integrating F incorporation and Al implantation in gate first scheme, valence band edge effect work function has been successfully achieved with slightly Jg degradation. Besides, the equivalent oxide thickness (EOT) scaling capability is also restricted in gate first scheme with high temperature thermal budget. For future device applications, a gate lat scheme suppressing high temperature steps is proposed. Experimental results of I/V, C/V and energy dispersive X-ray spectroscopy (EDS) had evidenced the proposal is available for nano scale p-type MOSFET applications. Valence band edge effective work function and better EOT scaling capability have been demonstrated. By introducing suitable low temperature O2 post metal annealing, work function can be further improved without Jg degradation and EOT penalties. Furthermore, EDS depth profiling through metal gate stacks also revealed that the oxygen content controlled the p-type metal gate work function.

並列關鍵字

High k ； Metal gate electrode ； Work function

參考文獻

[1.23] H. -S. Jung, J. -H. Lee, S. K. Han, Y. -S. Kim, H. J. Lim, M. J. Kim, S. J. Doh, M. Y. Yu, N. -I. Lee, H. -L. Lee1, T. -S. Jeon, H. -J. Cho, S. B. Kang, S. Y. Kim, I. S. Park, D. Kim, H. S. Baik, and Y. S. Chung, “A highly manufacturable MIPS (metal inserted poly-Si stack) technology with novel threshold voltage control”, VLSI Symp. Tech. Dig., pp. 232–233, 2005.

[1.15] S. C. Song, Z. B. Zhang, M. M. Hussain, C. Huffman, J. Barnet, S. H. Bae, H. J. Li, P. Majhi, C. S. Park, B. S. Ju, H. K. Park, C. Y. Kang, R. Choi, P. Zeitzoff, H. Tseng, B. H. Lee, and R. Jammy, “Highly Manufacturable 45 nm LSTP CMOSETs Using Novel Dual High-k and Dual Metal Gate CMOS Integration”, VLSI Symp. Tech. Dig., pp. 13–14, 2006.

[3.3] S. C. Song, Z. B. Zhang, M. M. Hussain, C. Huffman, J. Barnet, S. H. Bae, H. J. Li, P. Majhi, C. S. Park, B. S. Ju, H. K. Park, C. Y. Kang, R. Choi, P. Zeitzoff, H. Tseng, B. H. Lee, and R. Jammy, “Highly Manufacturable 45 nm LSTP CMOSETs Using Novel Dual High-k and Dual Metal Gate CMOS Integration”, VLSI Symp. Tech. Dig., pp. 13–14, June 2006.

[1.12] F. Y. Yen, C. L. Hung, Y. T. Hou, P. F. Hsu, V. S. Chang, P. S. Lim, L. G. Yao, J. C. Jiang, H. J. Lin, C. C. Chen, Y. Jin, S. M. Jang, H. J. Tao, S. C. Chen, and M. S. Liang, “Effective Work Function Engineering of TaxCy Metal Gate on Hf-based Dielectricd”, IEEE Electron Device Lett., vol. 28, no. 3, pp. 201–203, 2007.

[1.2] G. D. Wilk, R. M. Wallace, and J. M. Anthony, “High-κ gate dielectrics: Current status and materials properties considerations” J. Appl. Phys., vol. 89, no. 10, pp. 5243–5275, 2001.

國際替代計量

奈米級P型高介電/金屬閘極之金氧半電晶體製程最佳化與有效功函數調控的研究

全文下載

主題瀏覽