本研究主要探討以矽晶片為底材之樣品，於二次離子質譜儀分析時受外加之電子槍照射下，二次正離子產出率之變化。此論文針對不同的一次入射離子源(氧、氬及銫)，改變電子槍之能量與電流，觀察不同元素的二次正離子產出率之變化。
以高濃度硼氟離子佈植矽晶片為分析樣品，兩組實驗數據分別比較分析時電子槍不開與開電流100微安培時二次離子產出率的增加量，質譜實驗觀察顯示，增加量最多的為氟離子39倍，相對的硼離子只有~50%的增加量。為了更深入了解多於的離子被離子化的正確垂直樣品表面之空間分佈，我們使用離子能譜解析硼、氟及矽離子的能量分佈。實驗過程中我們預先於樣品表面施予2000伏特之正電位並藉由改變樣品上之電壓(正負50伏特)來接收不同能量的離子分佈。由能譜的實驗結果我們發現氟原子被外加電子槍照射後額外被離子化的原因有二: 第一，部分氟離子化來自於樣品表面的”電子束激發脫附(electron beam stimulated desorption)”第二，部分氟離子化來自於樣品表面上方的氣態分子，被外加的電子轟擊所所產生的離子化過程(post-ionization)。反觀硼及矽原子，只有額外少量多餘的離子化發生於樣品表面，並且無任何離子化產生於樣品上方。由硼離子的縱深分析結果發現，二次硼離子產出的增加量與電子槍照射樣品上之電流呈線性正比，這證實了當二次離子質譜儀以氧槍作分析時，外加電子會產生額外多餘微量的”便尼離子化過程”(Penning ionization)的存在。
便尼離子化過程是由於氧分子被電子撞擊後激發成較不穩定的激發態，此激發態的氧分子更易與周圍原子發生化學反應而造成離子化反應。實驗顯示，離子的增加量與電子束能量有強烈相關性。當我們固定電子束電流於30微安培時，分別改變電子槍的能量由3000，6000，9000到12000伏特，硼離子的增加量分別為21，29，40及60%，而矽離子的增加量分別為25，31，42及66%。
為了了解不同元素的便尼離子化的程度，我們取鋰，鈣，鈦，鎂及硼離子佈植樣品針對鋰，鈣，鈦，鎂，硼及矽之二次離子觀察期增加量變化。由縱深分析實驗結果顯示離子增加量與電子束電流呈線性正比。當電子束電流固定於90微安培時，鋰，鈣，鈦，鎂，硼及矽之二次離子增加量分別為0.1，1.6，6.1，26.4，59.2及71.4%。便尼離子化過程造成二次離子增加量與元素所需之離子化能量呈指數正比。由於便尼離子化過程是由於激態氧不穩定所造成的多餘離子化過程，所以我們試著以不同的一次離子源取代氧離子分析。當一次離子源由氬及銫取代氧離子分析時，實驗結果發現並無任何的二次離子增加量，此實驗結果也證實了便尼離子化過程只有使用一次氧離子源分析時會產生。

In this thesis, we study the positive secondary ion yield enhancement by addition electron beam irradiation in regular secondary ion mass spectrometry (SIMS) measurements.
Secondary ion emission was enhanced by electron beam in a typical SIMS operation, which was demonstrated using the shallow p/n junction implanted with BF2+ ions of a dosage of 2.3E15 cm-2 at 20 keV. In the SIMS mass spectra measurements, the 19F+ signal is enhanced by 39 times at an electron beam current of 100 μA. In contrast, the 11B+ signal is slightly enhanced by a factor of ~50%. In order to characterize the spatial distribution of secondary ions along the surface normal direction, the energy spectra of 19F+, 11B+ and 30Si+ ions were measured by altering the sample potential by ±50 V (relative the original sample bias 2 kV). The energy spectra reveal that most 19F+ ion signal is generated by electron beam stimulated desorption on the sample surface and some by the electron induced post-ionization in the gas phase above the sample surface. In contrast, only small enhancements of 11B+ and 30Si+ occur on the sample surface. No 11B+ and 30Si+ ions are generated in the gas phase above the sample surface. The enhancement of 11B+ increases linearly with electron beam current based on the depth profile data of 11B+. This supports the occurrence of Penning ionization for 11B+ on the sample surface. The ionization enhancement of 11B+ is dominated by oxygen radicals O2*.
The ionization enhancement strongly depended on the electron impact energy. The enhancement factors of the 11B+ and 30Si+ signals increase linearly with electron beam current. At an electron beam current of 50 nA, the 11B+ enhancement factor reaches ~21, ~29, ~40 and ~60% at electron beam energies of 3, 6, 9 and 12keV, respectively. Similarly, the 30Si+ enhancement factor reaches ~25, ~31, ~42 and ~66% at 3, 6, 9 and 12 keV electron beam energies, respectively.
The enhancement of secondary ion signals has been also investigated for the Si(100) wafers implanted with different chemical elements. The 7Li+, 40Ca+, 50Ti+, 24Mg+, 11B+ and 30Si+ secondary ion signals increase linearly with electron beam current at different rates, supported by the SIMS depth profiles. An enhancement factor (e-factor) is defined to characterize the increased percentage of a secondary ion signal. The 7Li+, 40Ca+, 50Ti+, 24Mg+, 11B+ and 30Si+ secondary ion signals exhibit e-factors of 0.1, 1.6, 6.1, 26.4, 59.2 and 71.4%, respectively at an electron beam current of 90 □A. The e-factor increases in an exponential function with ionization potential. A proposed Penning ionization mechanism on the sample surface can well explain the experimental results. The Penning ionization is dominated by the oxygen radicals since no secondary ion enhancements were observed when the O2+ primary ion was replaced by Cs+ and Ar+ in SIMS operations.

Chapter 1 References

[1] A. Benninghoven, F.G. Rudenauer and H.W. Werner, Secondary Ion Mass Spectrometry, Wiley, New York, 1987.
[2] R.G. Wilson, F.A. Stevie and C.W Magee, Secondary Ion Mass Spectrometry, Wiley, New York, 1989.
[3] J.C. Vickerman, A. Brown and N. Reed, Secondary Ion Mass Spectrometry: Principles and Applications, Oxyford University Press, New York, 1989.
[4] H. Oechsner, Analysis of electrically nonconducting sample structures with electron and mass spectroscopic methods, Thin Solid Films, 341 (1999) 105.
[5] Y. Higashi, Quantitative depth profiling by laser-ionization sputtered neutral mass spectrometry, Spectrochimica Acta Part B, 54 (1999) 109.
[6] P. Williams, V. R. Deline, C. A. Evans, Jr., W. Katz, Mechanism of the SIMS matrix effect, J. Appl. Phys., 33 (1978) 832.
[7] Smith, G.C., Quantitative Surface Analysis for Materials Science, The Institute of Metals, London, 1991.

Chapter 2 References

[1] Peter R. Ogilby, Singlet Oxygen-Introduction, Photochemistry and Photobiology. 82 (2006) 1133.
[2] David R. Kearns, Physical and chemical properties of singlet molecular oxygen, Chemical Reviews. 71 (1971) 395.
[3] R.S. Mulliken, Interpretation of the atmospheric oxygen bands; electronic levels of the oxygen molecule, Nature Journal. 122 (1928) 505.
[4] Wei-Chiang Lee, J. Hwang, Secondary ion emission enhancement assisted by electron beam in secondary ion mass spectrometry, Int. J. Mass Spectrom. 274 (2008) 25.
[5] Wei-Chiang Lee, J. Hwang, Penning ionization in the electron beam assisted secondary ion mass spectrometry-effect of electron impact energy, Int. J. Mass Spectrom. (accepted Oct. 2008).
[6] A Corney, O.M. Williams, Measurement of the radiative lifetime of the 1S0 metastable level of atomic oxygen, J. Phys. B: Atom. Mol. Phys. 5 (1972) 686.
[7] P. E. Siska, Molecular-beam studies of Penning ionization, Rev. Mod. Phys. 65 (1993) 337.
[8] R.L. Sharpless, T.G. Slanger, Surface chemistry of metastable oxygen. II. Destruction of O2(a1∆g), J. Chem. Phys. 91 (1989) 7947.
[9] B. Carol Johnson, Peter L. Smith and R.D. Knight, The radiative lifetime of the 5S20 metastable level of O++, The Astrophys. J. 281 (1984) 477.
[10] 郭正靈、許瑞榮、蘇漢宗、李羅權，高空大氣放電現象的多樣性與複雜性，物理雙月刋，21 (1999) 409.
[11] Hsu, R. R., H. T. Su, A. B. Chen, L. C. Lee, M. Asfur, C. Price, Y. Yair, Transient luminous events in the vicinity of Taiwan, J. Atmos. Sol. Terr. Phys. 65 (2003) 561.
[12] Su, H. T., R. R. Hsu, A. B. Chen, Y. C. Wang, W. S. Hsiao, W. C. Lai, L. C. Lee, M. Sato, H. Fukunishi, Gigantic jets between a thundercloud and the ionosphere, Nature. 423 (2003) 974.
[13] Vallance Jones, Aurora, D. Reidel, Norwell Mass. (1974).
[14] A Benninghoven, F G Rudenauer and H Werner, Secondary Ion Mass Spectrometry: Basic Concepts, Instrumental Aspects, Applications and Trends, John Wiley & Sons, New York. 1987.
[15] V. Cherepin, Secondary Ion Mass Spectroscopy of Solid Surfaces, VNW Science Press, Ultrecht. (1987).
[16] John C. Vickerman, Alan Brown, Nicola M. Reed, Secondary Ion Mass Spectrometry, Clarendon Press Oxford, (1989).
[17] J. C. C. Tsai, J. M. Morabito, The mechanism of simultaneous implantation and sputtering by high energy oxygen ions during secondary ion mass spectrometry (SIMS) analysis, Surface science. 44 (1974) 247.
[18] Y. Gao, H.N. Migeon, M. Juhel and J. Lecart, Enhanced SIMS analysis performance by CCl4 flooding technique, Surf. Interface Anal. 20 (1993) 716.
[19] J Sielanko, J Filiks, M Sowa, J Zinkiewicz, M Drewniak, The freon flooding technique in SIMS analysis, Vacuum. 46 (1995) 1459.
[20] W. Reuter, Secondary ion emission from metal targets under carbon trifluoride ion (CF3+) and oxygen ion (O2+) bombardment, Anal. Chem. 59 (1987) 2081
[21] G. Gillien, M. Walker, P Thompson, J. Bennett, Use of an SF5+ polyatomic primary ion beam for ultrashallow depth profiling on an ion microscope secondary ion mass spectroscopy instrument, J. Vac. Sci. Technol. B 18 (1) (2000) 503.
[22] G. Gillen, L. King, B. Freibaum, R. Lareau, J. Bennett, F. Chmara, Negative cesium sputter ion source for generation cluster primary ion beams for secondary ion mass spectrometry analysis, J. Vac. Sci. Technol. A 19 (2) (2001) 568.
[23] R. Liu, C. M. Ng, A. T. S. Wee, Ultra shallow secondary ion mass spectrometry, Solid-State and Integrated-Circuit Technology, 2001 - ieeexplore.ieee.org.
[24] R. Jede, H. Peters, G. Dunnebier, O. Ganschow, U. Kaiser, K. Seifert, Quantitative depth profile and bulk analysis with high dynamic range by electron gas sputtered neutral mass spectrometry, J. Vac. Sci. Technol. A. 6 (1988) 2271.
[25] Gunther K. Nicolussi, Michael J. Pellin, Keith R. Lykke, Jennifer L. Trevor, Donald E. Mencer, Andrew M. Davis, Surface Analysis by SNMS: Femtosecond Laser Postionization of Sputtered and Laser Desorbed Atoms, Surf. Interface Anal. 24 (1996) 363.
[26] Wolfgang Husinsky, Gerhard Betz, Fundamental aspects of SNMS for thin film characterization: experimental studies and computer simulations, Thin Solid Films. 272 (1996) 289.
[27] H. Oechsner, Analysis of electrically non-conducting sample structures with electron and mass spectroscopic methods, Thin Solid Films. 341 (1999) 105.
[28] Y. Higashi, Quantitative depth profiling by laser-ionization sputtered neutral mass spectrometry, Spectrochimica Acta Part B. 54 (1999) 109.
[29] H. Shichi, S. Osabe, M. Sugaya, T.Ino, H. Kakibayashi, K. Kanehori, Y. Mitsui, A resonance photoionization sputtered neutral mass spectrometry instrument for submicron microarea analysis of ULSI devices, Appl. Surf. Sci. 203 (2003) 228.
[30] Smith, G. C., Quantitative Surface Analysis for Materials Science, The institute of Metals, London, 1991.
[31] P. Williams, V. R. Deline, C. A. Evans, Jr., W. Katz, J. Appl. Phys. 52 (1984) 530.
[32] Klaus Franzreb, Jan Lorincik, Peter Williams, Quantitative study of sputtered ion yield. I. Argon ion bombardment of a silicon surface with O2 flood, Surface Science. 573 (2004) 291.
[33] P. E Siska, Molecular-beam studies of Penning ionization, Reviews of Modern Physics. 65 (1993) 337.
[34] Mustafa Akbulut, Norbert J. Sack, Theodore E. Madey, Elastic and inelastic processes in the interaction of 1-10eV ions with solids: ion transport through surface layers, Surface Science reports. 28 (1997) 177.
[35] A.M. Lanzillotto, C.W. Magee. Electron stimulated desorption effects in secondary ion emission from BF2+ implanted SiO2, J. Vac. Sci. Technol. A 8 (1990) 983.

Chapter 3 References

[1] Slodzian, G., Etude d’une method d’analyse I’emission ionique secondaire, Ann. Phys. 9 (1964) 1.
[2] V. Cherepin, Secondary Ion Mass Spectroscopy of Solid Surfaces, VNW Science Press, Ultrecht. (1987).
[3] IMS 6F / IMS 1270 user’s guide, reference No. 45 402 615., (1995).
[4] S. E. Van Bramer, An Introduction to Mass Spectrometry, Lecture Notes. (1997).
[5] T. Stephan, TOF-SIMS in cosmochemistry, Planet Space Sci. 49 (2001) 859.
[6] R.G. Wilson, F.A. Stevie and C.W Magee, Secondary Ion Mass Spectrometry, Wiley, New York, 1989.

Chapter 4 References

[1] R. Liu, CM. Ng, A.T.S. Wee. Ultra shallow secondary ion mass spectrometry. Solid-State and Integrated-Circuit Technology, 2001, ieeexplore.ieee.org.
[2] R. Jede, H. Peters, G. Dunnebier, O. Ganschow, U. Kaiser, K. Seifert. Quantitative depth profile and bulk analysis with high dynamic range by electron gas sputtered neutral mass spectrometry, J. Vac. Sci. Technol. A 6 (1988) 2271.
[3] Gunther K. Nicolussi, Michael J. Pellin, Keith R. Lykke, Jennifer L. Trevor, Donald E. Mencer, Andrew M. Davis. Surface analysis by SNMS: femtosecond laser postionization of sputtered and laser desorbed atoms, Surf. Interface Anal. 24 (1996) 363.
[4] Wolfgang Husinsky, Gerhard Betz. Fundamental aspects of SNMS for thin film characterization: experimental studies and computer simulations, Thin Solid Films. 272 (1996) 289.
[5] H. Oechsner. Analysis of electrically non-conducting sample structures with electron and mass spectroscopic methods, Thin Solid Films. 341 (1999) 105.
[6] Y. Higashi. Quantitative depth profiling by laser-ionization sputtered neutral mass spectrometry, Spectrochimica Acta Part B 54 (1999) 109.
[7] H. Shichi, S. Osabe, M. Sugaya, T.Ino, H. Kakibayashi, K. Kanehori, Y. Mitsui. A resonance photoionization sputtered neutral mass spectrometry instrument for submicron microarea analysis of ULSI devices, Appl. Surf. Sci. 203-204 (2003) 228.
[8] A. Benninghoven, F.G. Rudenauer, H Werner, Secondary Ion Mass Spectrometry: Basic Concepts, Instrumental Aspects, Applications and Trends, John Wiley & Sons, New York. 1987.
[9] W Reuter, Secondary ion emission from metal targets under carbon trifluoride ion (CF3+) and oxygen ion (O2+) bombardment, Anal Chem. 59 (1987) 2081.
[10] Y Gao, H.N. Migeon, M. Juhel, J. Lecart, Enhanced SIMS analysis performance by CCl4 flooding technique, Surf. Interface Anal. 20 (1993) 716.
[11] J. M. McKinley, F. A. Stevie, T. Neil, J. J. Lee, L.Wu, D. Sieloff, C. Granger. Depth profiling of ultra-shallow implants using a Cameca IMS-6f, J. Vac. Sci. Technol. B 18 (2000) 514.
[12] Victor K.F. Chia, Gary R. Mount, Michael J. Edgell, Charles W. Magee. Recent advances in secondary ion mass spectrometry to characterize ultralow energy ion implants, J. Vac. Sci. Technol. B 17 (1999) 2345.
[13] M.H. Yang, G. Mount, l. Mowat. Ultrashallow profiling using secondary ion mass spectrometry: estimating junction depth error using mathematical deconvolution, J. Vac. Sci. Technol. B 24 (2006) 428.
[14] M. Meuris, P. De Bisschop, J.F. Leclair, W. Vandervorst. Determination of the angle of incidence in a Cameca IMS-4f SIMS instrument, Surf. Interface Anal. 14 (1989) 739.
[15] Jiang Zhi-Xiong, Paul F.A. Alkemade, Eelke Algra, S. Radelaar. High depth resolution SIMS analysis with low-energy grazing O2+ beams, Surf. Interface Anal. 25 (1997) 285.
[16] M. Bernheim, G. Blaise, G.Slodzian. Sur la formation retardee d’ions a l’exterieur d’une cible soumise a un bombardement ionique, Int. J. Mass Spectrom. Ion Phys. 10 (1972) 293.
[17] A.M. Lanzillotto, C.W. Magee. Electron stimulated desorption effects in secondary ion emission from BF2+ implanted SiO2, J. Vac. Sci. Technol. A 8 (1990) 983.
[18] D.S. McPhail, M.G. Dowsett, E.H.C. Parker. Profile distortion during secondary ion mass spectrometry analyses of resistive layers due to electron stimulated desorption and charging, J. Appl. Phys. 60 (1986) 2573.
[19] Berta Guzman de la Mat, DowettF Mark G., Ion and electron bombardment-related ion emission during the analysis of diamond using secondary ion mass spectrometry, J. Appl. Phys. 101 (2007) 034910-1.
[20] J Sielanko, J Filiks, M Sowa, J Zinkiewicz, M Drewniak. The freon flooding technique in SIMS analysis, Vacuum. 46 (1995) 1459.
[21] A Corney, O.M. Williams, Measurement of the radiative lifetime of the 1S0 metastable level of atomic oxygen, J. Phys. B: Atom. Mol. Phys. 5 (1972) 686.
[22] P. E. Siska. Molecular-beam studies of Penning ionization, Rev. Mod. Phys. 65 (1993) 337.
[23] R.L. Sharpless, T.G. Slanger, Surface chemistry of metastable oxygen. II. Destruction of O2(a1∆g), J. Chem. Phys. 91 (1989) 7947.
[24] B. Carol Johnson, Peter L. Smith and R.D. Knight, The radiative lifetime of the 5S20 metastable level of O++, The Astrophys. J. 281 (1984) 477.
[25] K. Wittmaack. Current density effects in secondary ion emission studies, Nucl. Instrum. Methods. 132 (1976) 381.
[26] Hubert Gnaser. Singly- and doubly-negative carbon clusters in sputtering: energy abundance distributions and unimolecular fragmentation, Nucl. Instrum. Methods Phys. Res. B 149 (1999) 38.

Chapter 5 References

[1] Wei-Chiang Lee and J. Hwang, Secondary ion emission enhancement assisted by electron beam in secondary ion mass spectrometry, Int. J. Mass Spectrom. 274 (2008) 25.
[2] 郭正靈、許瑞榮、蘇漢宗、李羅權，高空大氣放電現象的多樣性與複雜性，物理雙月刋，21 (1999) 409.
[3] Hsu, R. R., H. T. Su, A. B. Chen, L. C. Lee, M. Asfur, C. Price, Y. Yair, Transient luminous events in the vicinity of Taiwan, J. Atmos. Sol. Terr. Phys. 65 (2003) 561.
[4] Su, H. T., R. R. Hsu, A. B. Chen, Y. C. Wang, W. S. Hsiao, W. C. Lai, L. C. Lee, M. Sato, H. Fukunishi, Gigantic jets between a thundercloud and the ionosphere, Nature. 423 (2003) 974.
[5] M. Meuris, P. De Bisschop, J.F. Leclair, W. Vandervorst. Determination of the angle of incidence in a Cameca IMS-4f SIMS instrument, Surf. Interface Anal. 14 (1989) 739.
[6] Jiang Zhi-Xiong, Paul F.A. Alkemade, Eelke Algra, S. Radelaar. High depth resolution SIMS analysis with low-energy grazing O2+ beams, Surf. Interface Anal. 25 (1997) 285.
[7] M. Bernheim, G. Blaise, G.Slodzian, Sur la formation retardee d’ions a l’exterieur d’une cible soumise a un bombardement ionique, Int. J. Mass Spectrom. Ion Phys. 10 (1972) 293.
[8] Berta Guzman de la mat, Mark G. Dowett, Ion and electron bombardment-related ion emission during the analysis of diamond using secondary ion mass spectrometry, J. Appl. Phys. 101 (2007) 034910-1.
[9] J Sielanko, J Filiks, M Sowa, J Zinkiewicz, M Drewniak, The freon flooding technique in SIMS analysis, Vacuum. 46 (1995) 1459.
[10] P. E Siska, Molecular-beam studies of Penning ionization, Reviews of Modern Physics. 65 (1993) 337.
[11] Vallance Jones, Aurora, D. Reidel, Norwell Mass. (1974).
[12] Z. J. Ding, H. M. Li, K. Goto, Y. Z. Jiang, R. Shimizu, Energy spectra of backscattered electrons in Auger electron spectroscopy: comparison of Monte Carlo simulation with experiment, J. Appl. Phys. 96 (2004) 4598.

Chapter 6 References

[1] R. Liu, C.M. Ng, A.T.S. Wee. Ultra shallow secondary ion mass spectrometry, Solid-State and Integrated-Circuit Technol. (2001), http:// ieeexplore.ieee.org.
[2] A. Benninghoven, F.G Rudenauer, H. Werner, Secondary Ion Mass Spectrometry: Basic Concepts, Instrumental Aspects, Applications and Trends, John Wiley & Sons, New York, 1987.
[3] W. Reuter, Secondary ion emission from metal targets under carbon trifluoride ion (CF3+) and oxygen ion (O2+) bombardment, Anal. Chem. 59 (1987) 2081.
[4] Y. Gao, H.N. Migeon, M. Juhel, J. Lecart, Enhanced SIMS Analysis Performance by CCl4 Flooding Technique, Surf and Interf Anal. 20 (1993) 716.
[5] Wei-Chiang Lee and J. Hwang, Secondary ion emission enhancement assisted by electron beam in secondary ion mass spectrometry, Int. J. Mass Spectrom. 274 (2008) 25.
[6] J. Sielanko, J. Filiks, M. Sowa, J. Zinkiewicz, M. Drewniak, The freon flooding technique in SIMS analysis, Vacuum. 46 (1995) 1459.
[7] V.R. Deline, C.A. Evans, Jr., P. Williams, A unified explanation for secondary ion yields, Appl. Phys. Lett. 33 (1978) 578.
[8] B.G. Wilson, F.A. Stevie, C.W. Magee, Secondary Ion Mass Spectrometry, John Wiley & Sons, 1989, p.3.3-1.
[9] A. Corney, O.M. Williams, Measurement of the radiative lifetime of the 1S0 metastable level of atomic oxygen, J. Phys. B: Atom. Molec. Phys. 5 (1972) 686.
[10] P.E. Siska. Molecular-beam studies of Penning ionization, Rev. Modern Physics, 65 (1993) 337.
[11] R.L. Sharpless, T.G. Slanger. Surface chemistry of metastable oxygen. II. Destruction of O2(a1∆g), J. Chem. Phys. 91 (1989) 7947.
[12] B. Carol Johnson, Peter L. Smith, R. D. Knight, The radiative lifetime of the 5S20 metastable level of O++, Astrophysical J. 281 (1984) 477.
[13] Berta Guzman de la mat, Mark G. Dowett, Ion and electron bombardment-related ion emission during the analysis of diamond using secondary ion mass spectrometry, J. Appl. Phys. 101 (2007) 034910-1.