本研究中使用雙極脈衝直流反應式濺鍍沉積氮化鋁薄膜於矽基板上，並建立一個機器學習薄膜品質分類器來進行薄膜品質預測。實驗中利用調整濺鍍製程參數氬氣和氮氣的混氣比，進行不同結晶性質的氮化鋁薄膜製備及薄膜品質量測，完成的樣本將提供給機器學習分類器訓練使用。製程中利用光放射光譜儀(Optical Emission Spectroscopy, OES)測量電漿放射出的鋁光譜強度進行分析，在各種混氣比條件下，得到瞬態反應濺鍍模式(N2:Ar = 7:30)及介電反應濺鍍模式(N2:Ar = 45:15)區間，在這二種區間進行薄膜樣本的濺鍍。FTIR光譜顯示出濺鍍出的薄膜具有Al-N鍵的振動模式引起的吸收帶，峰寬隨脈衝頻率上升(75 kHz~250 kHz)而變窄(166~192 cm-1)，可視為氮化鋁薄膜結構的改善。最後通過XRD量測證實氮化鋁薄膜的結晶相，以此歸類出結晶與非晶的氮化鋁薄膜。
本研究最終目標為建立出氮化鋁薄膜的結晶性質分類器。通過對製程中光放射光譜數據進行主成分分析(PCA)，得到不同製程條件之樣品數據的第一~第四特徵向量(PC1~PC4)，經結晶性質比對，訓練數據採用分辨率較高的PC2、PC3。將主成分分析完成的數據集利用支援向量機(SVM)進行訓練分類，並使用不同核函數：高斯核函數(Gaussian kernel)、徑向基核函數(Radial basis function kernel, RBF)及多項式核函數(Polynomial kernel)來進行分類邊界計算，訓練出不同核函數的分類器模型。所訓練之分類器模型藉由輸入其他驗證樣本的光放射光譜數據，並比對驗證樣本實際量測的結晶性質結果，可驗證不同核函數分類器對於預測氮化鋁薄膜結晶性質的準確性，結果顯示，高斯核函數演算法能夠建立較高準確率(90%)的氮化鋁結晶性質分類器。

In this study, we report pulsed direct current reactive magnetron sputtering deposited aluminum nitride (AlN) films with the employment of in-situ diagnostics tool of optical emission spectroscopy (OES) for plasma chemistry monitoring. Effect of flow ratio of nitrogen/argon on structural evolutions of the deposited AlN films were systematically investigated by various tools of Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction spectroscopy (XRD). In addition, principal component analysis (PCA) was performed to establish the correlations between the plasma chemistry (OES spectra) and crystal structure of deposited AlN thin films. The second and third principal component (PC2 and PC3) of the sample data was combined with the support vector machine (SVM) algorithm method to group the crystallization and amorphous OES spectral data. The support vector machine (SVM) method can classificated by using three different kernel function methods, include the Gaussian kernel, the polynomial kernel and the radial basis function kernel. The results show that the Gaussian kernel function can establish a Classifiers of AlN crystal properties with high accuracy (90%).

[1] Zywitzki, O. & Hoetzsch, G. Influence of coating parameters on the structure and properties of Al2O3 layers reactively deposited by means of pulsed magnetron sputtering. Surface and Coatings Technology 86–87, 640–647 (1996).
[2] Jones, K. A. et al. AlN as an encapsulate for annealing SiC. Journal of Applied Physics 83, 8010–8015 (1998).
[3] Vacandio, F. et al. Improvement of the electrochemical behaviour of AlN films produced by reactive sputtering using various under-layers. Electrochimica Acta 46, 3827–3834 (2001).0.
[4] Wang, X. & Yoshikawa, A. Molecular beam epitaxy growth of GaN, AlN and InN. Progress in Crystal Growth and Characterization of Materials 48–49, 42–103 (2004).
[5] Auger, M. A., V?zquez, L., Jergel, M., Snchez, O. & Albella, J. M. Structure and morphology evolution of ALN films grown by DC sputtering. Surface and Coatings Technology 180–181, 140–144 (2004).
[6] Mahmood, A. et al. Optical and surface analysis of DC-reactive sputtered AlN films. Diamond and Related Materials 12, 1315–1321 (2003).
[7] Altun, H. & Sen, S. The effect of DC magnetron sputtering AlN coatings on the corrosion behaviour of magnesium alloys. Surface and Coatings Technology 197, 193–200 (2005).
[8] Vissutipitukul, P. & Aizawa, T. Wear of plasma-nitrided aluminum alloys. Wear 259, 482–489 (2005).
[9] Yao, S. H., Su, Y. L., Kao, W. H. & Liu, T. H. Tribology and oxidation behavior of TiN/AlN nano-multilayer films. Tribology International 39, 332–341 (2006).
[10] Sproul, W. High-rate reactive DC magnetron sputtering of oxide and nitride superlattice coatings. Vacuum 51, 641–646 (1998).
[11] Oliveira, I. C., Grigorov, K. G., Maciel, H. S., Massi, M. & Otani, C. High textured AlN thin films grown by RF magnetron sputtering; composition, structure, morphology and hardness. Vacuum 75, 331–338 (2004).
[12] Zhang, J. X. et al. Growth of AlN films on Si (100) and Si (111) substrates by reactive magnetron sputtering. Surface and Coatings Technology 198, 68–73 (2005).
[13] Guo, Q. X., Yoshitugu, M., Tanaka, T., Nishio, M. & Ogawa, H. Microscopic investigations of aluminum nitride thin films grown by low-temperature reactive sputtering. Thin Solid Films 483, 16–20 (2005).
[14] M. Quirk and J. Serda, Semiconductor Manufacturing Technology, Ch.11 Deposition, 2001
[15] 莊達人，VLSI 製造技術，高立圖書有限公司，1996年。
[16] Venables, J. A. & Spiller, G. D. T. Nucleation and Growth of Thin Films. in Surface Mobilities on Solid Materials (ed. Binh, V. T.) 341–404 (Springer US, 1983). doi:10.1007/978-1-4684-4343-1_16
[17] Schiller, S. et al. Pulsed magnetron sputter technology. Surface and Coatings Technology 61, 331–337 (1993).
[18] Kelly, P. J. & Arnell, R. D. Control of the structure and properties of aluminum oxide coatings deposited by pulsed magnetron sputtering. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 17, 945–953 (1999).
[19] Bradley, J. W., Bcker, H., Aranda-Gonzalvo, Y., Kelly, P. J. & Arnell, R. D. The distribution of ion energies at the substrate in an asymmetric bi-polar pulsed DC magnetron discharge. Plasma Sources Sci. Technol. 11, 165–174 (2002).
[20] Miyagi, T. et al. Pulse mode effects on crystallization temperature of titanium dioxide films in pulse magnetron sputtering. Thin Solid Films 442, 32–35 (2003).
[21] Benegra, M. et al. Residual stresses in titanium nitride thin films deposited by direct current and pulsed direct current unbalanced magnetron sputtering. Thin Solid Films 494, 146–150 (2006).
[22] Koski, K., Hls, J. & Juliet, P. Deposition of aluminium oxide thin films by reactive magnetron sputtering. Surface and Coatings Technology 116–119, 716–720 (1999).
[23] Bruer, G., Ruske, M., Szczyrbowski, J., Teschner, G. & Zmelty, A. Mid frequency sputtering with TwinMag?-a survey of recent results. Vacuum 51, 655–659 (1998).
[24] Sellers, J. Asymmetric bipolar pulsed DC: the enabling technology for reactive PVD. Surface and Coatings Technology 98, 1245–1250 (1998).
[25] Qiu, J.-Y., Hotta, Y., Watari, K., Mitsuishi, K. & Yamazaki, M. Low-temperature sintering behavior of the nano-sized AlN powder achieved by super-fine grinding mill with Y2O3 and CaO additives. Journal of the European Ceramic Society 26, 385–390 (2006).
[26] Belkind, A. et al. Characterization of pulsed dc magnetron sputtering plasmas. New J. Phys. 7, 90–90 (2005).
[27] Okano, H., Takahashi, Y., Tanaka, T., Shibata, K. & Nakano, S. Preparation of c -Axis Oriented AlN Thin Films by Low-Temperature Reactive Sputtering. Jpn. J. Appl. Phys. 31, 3446–3451 (1992).
[28] Tanaka, Y., Hasebe, Y., Inushima, T., Sandhu, A. & Ohoya, S. Comparison of AlN thin films grown on sapphire and cubic-SiC substrates by LP-MOCVD. Journal of Crystal Growth 209, 410–414 (2000).
[29] Roman, Y. G. & Adriaansen, A. P. M. Aluminium nitride films made by low pressure chemical vapour deposition: Preparation and properties. Thin Solid Films 169, 241–248 (1989).
[30] Ishihara, M., Yamamoto, K., Kokai, F. & Koga, Y. Effect of Laser Wavelength for Surface Morphology of Aluminum Nitride Thin Films by Nitrogen Radical-Assisted Pulsed Laser Deposition. Jpn. J. Appl. Phys. 40, 2413–2416 (2001).
[31] M. Schneider and W. D. Sproul, in Handbook of Thin Film Process Technology: 98/1 Reactive Sputtering, edited by W. D. Westwood ~IOP, Bristol, 1998
[32] Chapman, B., Glow Discharge Processes, John Wiley & Sons lnc, 1980.
[33] 羅正忠，半導體製程技術導論，歐亞出版社，2006 年。
[34] I. H. Hutchinson, Principles of Plasma Diagnostics 2nd, Cambridge University Press, 2002.
[35] Chodun, R., Nowakowska-Langier, K. & Zdunek, K. Methods of optimization of reactive sputtering conditions of Al target during AlN films deposition. Materials Science-Poland 33, 894–901 (2015).
[36] Tristant, P. et al. Microwave plasma enhanced CVD of aluminum oxide films: OES diagnostics and influence of the RF bias. Thin Solid Films 390, 51–58 (2001).
[37] Auger, M. A., Vzquez, L., Jergel, M., Snchez, O. & Albella, J. M. Structure and morphology evolution of ALN films grown by DC sputtering. Surface and Coatings Technology 180–181, 140–144 (2004).
[38] Sanz-Hervs, A., Iborra, E., Clement, M., Sangrador, J. & Aguilar, M. Influence of crystal properties on the absorption IR spectra of polycrystalline AlN thin films. Diamond and Related Materials 12, 1186–1189 (2003).
[39] Hanada, T., Kobayashi, M., Tanabe, S. & Soga, N. Preparation and physical properties of rf-sputtered amorphous films in the Al2O3AlN system. Journal of Non-Crystalline Solids 135, 227–235 (1991).
[40] Jacquot, A. et al. Optical and thermal characterization of AlN thin films deposited by pulsed laser deposition. Applied Surface Science 186, 507–512 (2002).
[41] Hao, X.-P. et al. Synthesize AlN nanocrystals in organic solvent at atmospheric pressure. Journal of Crystal Growth 242, 229–232 (2002).
[42] Garca Molleja, J. et al. AlN thin films deposited by DC reactive magnetron sputtering: effect of oxygen on film growth. Eur. Phys. J. Appl. Phys. 64, 20302 (2013).
[43] Lu, Y. F. et al. Ion-assisted pulsed laser deposition of aluminum nitride thin films. Journal of Applied Physics 87, 1540–1542 (2000).