团簇源中团簇形成的DSMC模拟研究
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摘要
团簇沉积成薄膜作为一种新的制膜技术而受到广泛的关注。它不仅能生长通常方法难以复合的薄膜材料,而且还能在比分子束外延法所需温度较低的条件下进行。目前这一技术已被用来制备高性能金属、半导体、氧化物、硫化物和有机薄膜等。由于膜的性质由团簇的性质影响,所以对团簇的形成过程的研究尤为重要。本论文中,我们利用直接模拟蒙特卡洛方法(DSMC),用Fortran语言汇编程序并自建模型,研究了在气体凝聚团簇源和磁控溅射气体凝聚团簇源中影响团簇生长的各因素。该论文的具体内容及结果归纳如下：
1.模拟了气体凝聚团簇源在不同的腔长,不同的腔壁温度和不同惰性气体的含量的条件下,Cu团簇的尺寸分布。模拟结果表明：腔的长度越长,产生大团簇的比例越大；腔壁的温度越低,产生的大团簇的比例越大；惰性气体的含量比例越高,产生的大团簇的比例越小；相同的惰性气体含量下,He/Ar比值越高,产生大团簇的比例越大。
2.模拟了气体凝聚团簇源的引出口尺寸和中心位置不同的条件下,Cu团簇的尺寸分布以及模拟了随着时间的增长,腔内团簇数目的变化。模拟结果表明：引出口的直径越大,产生大团簇的比例越小；在引出口的直径相同的情况下,引出口的中心位置偏离坐标原点比在原点产生的大团簇的比例要大；随着时间的增长,腔内团簇数目先变多后变少。
3.模拟了磁控溅射气体团簇源中Cu+(Cu-)的含量比例不同的条件下,Cu团簇的尺寸分布。模拟结果表明：随着含量比例的增加,团簇的尺寸分布变窄了,不带电的团簇的比例增加,不带电的铜团簇分布的最大值减小；与气体凝聚团簇源中带电团簇的比例为零相比,相应的带正电荷和带负电荷团簇的比例先增加后减小；相同的含量比例下,带正电的团簇的尺寸分布与带负电荷的团簇的尺寸分布基本相同；初始Cu-比Cu+的含量比例大时,输出的主要是带负电荷的团簇,带正电荷和不带电的团簇占很小的比例；Cu-含量比例的增加,Cu-团簇的尺寸分布减小。
Thin films obtained by cluster deposition have attracted strong attention as a new manufacturing technique to realize thin film material that can't be produced in usual way in the temperature that is lower than that of molecular beam epitaxial method. At present, high performance metallic materials, semiconductor, oxide, sulfide, organic films are produced by this technique. Because the film's features are influenced by the cluster properties, so the study of the clusters growth processes is very important. In this paper, the factors affecting the growth of cluster are studied by direct simulation Monte Carlo method in gas aggregation cluster source and magnetron sputtering-gas aggregation cluster source and the program is compiled by Fortran language, the model is self-build. The content of this paper could be concluded as following:
1. In a gas aggregation cluster source, the size distributions of the Cu clusters in various experimental conditions such as growth length, out wall temperature and concentration of the inert gas are studied by direct simulation Monte Carlo method. The results show that size of cluster increases with the increase in the growth length, the size increases with the decrease in temperature and the number of big clusters decreases on increasing the concentration of the inert gas. Large clusters can be obtained after addition of He to the Ar in the same concentration of the inert gas.
2. In a gas aggregation cluster source, the size distributions of the Cu clusters in various sizes and central positions of the exit nozzle and the change of the number of clusters in the chamber with the increase in time are studied by direct simulation Monte Carlo method. The results show that that size of cluster increases with the decrease in the diameter of the exit nozzle; larger clusters can be obtain in this situation that the central positions deviate the origin of the coordinates; the number of clusters in the chamber increases with the increase in time in the initial stage; soon after that, the number of clusters in the chamber decreases with the increase in time.
3. In a magnetron sputtering-gas cluster source, the size distributions of the Cu clusters in various concentrations of the positive Cu or negative Cu gas are studied by direct simulation Monte Carlo method. The results show that the size distribution of clusters with no charge becomes narrower and the concentration and the maximum size of clusters with no charge become larger with the increase in the concentration of the positive Cu or negative Cu gas, oppositely the concentrations of clusters with positive or negative increase with the increasing of the concentration of the positive Cu, and then decrease comparing with having not charged Cu clusters in gas aggregation cluster source; the concentrations of clusters with positive or negative are roughly the same in the initial situation with same concentration. The main output is the negative clusters when the concentration of the negative Cu gas is larger than the concentration of the positive Cu gas; when the increasement of the concentration of the Cu gas, the size distribution of the negative Cu clusters becomes narrower.
1.模拟了气体凝聚团簇源在不同的腔长,不同的腔壁温度和不同惰性气体的含量的条件下,Cu团簇的尺寸分布。模拟结果表明：腔的长度越长,产生大团簇的比例越大；腔壁的温度越低,产生的大团簇的比例越大；惰性气体的含量比例越高,产生的大团簇的比例越小；相同的惰性气体含量下,He/Ar比值越高,产生大团簇的比例越大。
2.模拟了气体凝聚团簇源的引出口尺寸和中心位置不同的条件下,Cu团簇的尺寸分布以及模拟了随着时间的增长,腔内团簇数目的变化。模拟结果表明：引出口的直径越大,产生大团簇的比例越小；在引出口的直径相同的情况下,引出口的中心位置偏离坐标原点比在原点产生的大团簇的比例要大；随着时间的增长,腔内团簇数目先变多后变少。
3.模拟了磁控溅射气体团簇源中Cu+(Cu-)的含量比例不同的条件下,Cu团簇的尺寸分布。模拟结果表明：随着含量比例的增加,团簇的尺寸分布变窄了,不带电的团簇的比例增加,不带电的铜团簇分布的最大值减小；与气体凝聚团簇源中带电团簇的比例为零相比,相应的带正电荷和带负电荷团簇的比例先增加后减小；相同的含量比例下,带正电的团簇的尺寸分布与带负电荷的团簇的尺寸分布基本相同；初始Cu-比Cu+的含量比例大时,输出的主要是带负电荷的团簇,带正电荷和不带电的团簇占很小的比例；Cu-含量比例的增加,Cu-团簇的尺寸分布减小。
Thin films obtained by cluster deposition have attracted strong attention as a new manufacturing technique to realize thin film material that can't be produced in usual way in the temperature that is lower than that of molecular beam epitaxial method. At present, high performance metallic materials, semiconductor, oxide, sulfide, organic films are produced by this technique. Because the film's features are influenced by the cluster properties, so the study of the clusters growth processes is very important. In this paper, the factors affecting the growth of cluster are studied by direct simulation Monte Carlo method in gas aggregation cluster source and magnetron sputtering-gas aggregation cluster source and the program is compiled by Fortran language, the model is self-build. The content of this paper could be concluded as following:
1. In a gas aggregation cluster source, the size distributions of the Cu clusters in various experimental conditions such as growth length, out wall temperature and concentration of the inert gas are studied by direct simulation Monte Carlo method. The results show that size of cluster increases with the increase in the growth length, the size increases with the decrease in temperature and the number of big clusters decreases on increasing the concentration of the inert gas. Large clusters can be obtained after addition of He to the Ar in the same concentration of the inert gas.
2. In a gas aggregation cluster source, the size distributions of the Cu clusters in various sizes and central positions of the exit nozzle and the change of the number of clusters in the chamber with the increase in time are studied by direct simulation Monte Carlo method. The results show that that size of cluster increases with the decrease in the diameter of the exit nozzle; larger clusters can be obtain in this situation that the central positions deviate the origin of the coordinates; the number of clusters in the chamber increases with the increase in time in the initial stage; soon after that, the number of clusters in the chamber decreases with the increase in time.
3. In a magnetron sputtering-gas cluster source, the size distributions of the Cu clusters in various concentrations of the positive Cu or negative Cu gas are studied by direct simulation Monte Carlo method. The results show that the size distribution of clusters with no charge becomes narrower and the concentration and the maximum size of clusters with no charge become larger with the increase in the concentration of the positive Cu or negative Cu gas, oppositely the concentrations of clusters with positive or negative increase with the increasing of the concentration of the positive Cu, and then decrease comparing with having not charged Cu clusters in gas aggregation cluster source; the concentrations of clusters with positive or negative are roughly the same in the initial situation with same concentration. The main output is the negative clusters when the concentration of the negative Cu gas is larger than the concentration of the positive Cu gas; when the increasement of the concentration of the Cu gas, the size distribution of the negative Cu clusters becomes narrower.
引文
[1]Tembrello.T.A Cluster-solid interaction [J] Nucl Instr and Meth B 1995,99:225
[2]卢希庭,沈定予,王雪梅MeV微集团束与物质的相互作用[J]原子核物理评论1998,15(3)：150
[3]王广厚,团簇物理的新进展(Ⅰ),物理学进展,1994.12：121
[4]Walt A.de Heer The physicals of simple metal clusters:experimental aspects and simple models [J] Rev.Mod.Phys 1993,65(3):611
[5]H.Haberland, M. Mall, M.Moseler. Filling of micro-sized contact holes with copper by energetic cluster impact.[J] J.Vac.Sci.Technol.A.1994,6:12(5)
[6]H.Haberland Clusters of atoms and molecules [M] Berlin:Springer,1995:207
[7]M. Goto, J.Murakami, Y. Tai, K. Yoshimura, K. Igarashi, S. Tanemura Formation of alumina fine particles by magnetron sputtering-gas aggregation method [J] Z. Phys. D:At. Mol. Clusters 1997.40:115
[8]H.Mizuseki, Y.Jin, Y.Kawazoe, L.T.Wille Cluster growth processes by direct simulation Monte Carlo method [J] Appl. Phys. A 2001.73:731
[9]T. Hihara, K. Sumiyama Formation and size control of Ni cluster by plasma gas condensation [J] J. Appl. Phys.1998.84:5270
[10]C. Brechignac, P. Cahuzac, F. Carlier, M. Defrutos, A. Masson, J.P. Roux, Generation of rare earth metal clusters by means of the gas-aggregation technique [J] Z. Phys. D:At. Mol. Clusters 1991.19:195
[11]Boris Briehl, Herbert M. Urbassek Monte Carlo simulation of growth and decay processes in a cluster aggregation source [J] J. Vac. Sci. Tech. A.1998.17(1):256
[12]Bird G A. Approach to translational equilibrium in a rigid sphere gas [J] Phys.Fluids. 1963,6:1518～1519
[13]Bird G A Molecular Gas Dynamics.[M] Oxford:Claredon Press,1976
[14]Olynick D P,Moss J N.H A.Hassan AIAA paper 1988～2734,1988
[15]Bird G A. Rarefied gas daynamics,Invited paper 221 at the 12th international symposium on rarefied gas dynamics, Charlottesville, VA, July 1980
[16]Koura K, Matsumoto H. Variable soft sphere model for inverse power law or Lennard-Jones potential [J] Phys.Fluids,1991,3:2459～2465
[17]Vincenti W G. Kruger C H. Introduction to physical gas dynamics. [M] New York:Wiley. 1965.
[18]Hinshelwood C N. The kinetics of chemical change. [M] Oxford:Claredon Press.1940
[19]吴其芬,陈伟芳高温稀薄气体热化学非平衡流动的DSMC方法[M]长沙：国防科技大学出版社,1999
[20]H. Schaber, T. P. Martin Properties of a cluster source [J] Surf. Sci.1985.156:64
[21]Ibrahimkutty Shyjumon, Manesh Gopinadhan, Christiane A. Helm, Boris M. Smirnov, Rainer Hippler Deposition of titanium oxide clusters producted by magnetron sputtering [J] Thin Solid Films.2006.500:41
[22]A. N. Banerjee, R. Krishna and B. Das Size controlled deposition of Cu and Si nano-clusters by an ultra-high vacuum sputtering gas aggregation technique [J] Appl. Phys. A 2008.90:299
[23]F. Frank, W. Schulze, B. Tesche, J. Urban, B. Winter Formation of metal clusters and molecules by means of the gas aggregation technique and characterization of size distribution [J]Surf.Sci.1985.156:90
[2]卢希庭,沈定予,王雪梅MeV微集团束与物质的相互作用[J]原子核物理评论1998,15(3)：150
[3]王广厚,团簇物理的新进展(Ⅰ),物理学进展,1994.12：121
[4]Walt A.de Heer The physicals of simple metal clusters:experimental aspects and simple models [J] Rev.Mod.Phys 1993,65(3):611
[5]H.Haberland, M. Mall, M.Moseler. Filling of micro-sized contact holes with copper by energetic cluster impact.[J] J.Vac.Sci.Technol.A.1994,6:12(5)
[6]H.Haberland Clusters of atoms and molecules [M] Berlin:Springer,1995:207
[7]M. Goto, J.Murakami, Y. Tai, K. Yoshimura, K. Igarashi, S. Tanemura Formation of alumina fine particles by magnetron sputtering-gas aggregation method [J] Z. Phys. D:At. Mol. Clusters 1997.40:115
[8]H.Mizuseki, Y.Jin, Y.Kawazoe, L.T.Wille Cluster growth processes by direct simulation Monte Carlo method [J] Appl. Phys. A 2001.73:731
[9]T. Hihara, K. Sumiyama Formation and size control of Ni cluster by plasma gas condensation [J] J. Appl. Phys.1998.84:5270
[10]C. Brechignac, P. Cahuzac, F. Carlier, M. Defrutos, A. Masson, J.P. Roux, Generation of rare earth metal clusters by means of the gas-aggregation technique [J] Z. Phys. D:At. Mol. Clusters 1991.19:195
[11]Boris Briehl, Herbert M. Urbassek Monte Carlo simulation of growth and decay processes in a cluster aggregation source [J] J. Vac. Sci. Tech. A.1998.17(1):256
[12]Bird G A. Approach to translational equilibrium in a rigid sphere gas [J] Phys.Fluids. 1963,6:1518～1519
[13]Bird G A Molecular Gas Dynamics.[M] Oxford:Claredon Press,1976
[14]Olynick D P,Moss J N.H A.Hassan AIAA paper 1988～2734,1988
[15]Bird G A. Rarefied gas daynamics,Invited paper 221 at the 12th international symposium on rarefied gas dynamics, Charlottesville, VA, July 1980
[16]Koura K, Matsumoto H. Variable soft sphere model for inverse power law or Lennard-Jones potential [J] Phys.Fluids,1991,3:2459～2465
[17]Vincenti W G. Kruger C H. Introduction to physical gas dynamics. [M] New York:Wiley. 1965.
[18]Hinshelwood C N. The kinetics of chemical change. [M] Oxford:Claredon Press.1940
[19]吴其芬,陈伟芳高温稀薄气体热化学非平衡流动的DSMC方法[M]长沙：国防科技大学出版社,1999
[20]H. Schaber, T. P. Martin Properties of a cluster source [J] Surf. Sci.1985.156:64
[21]Ibrahimkutty Shyjumon, Manesh Gopinadhan, Christiane A. Helm, Boris M. Smirnov, Rainer Hippler Deposition of titanium oxide clusters producted by magnetron sputtering [J] Thin Solid Films.2006.500:41
[22]A. N. Banerjee, R. Krishna and B. Das Size controlled deposition of Cu and Si nano-clusters by an ultra-high vacuum sputtering gas aggregation technique [J] Appl. Phys. A 2008.90:299
[23]F. Frank, W. Schulze, B. Tesche, J. Urban, B. Winter Formation of metal clusters and molecules by means of the gas aggregation technique and characterization of size distribution [J]Surf.Sci.1985.156:90