SRIM程序.ppt

1、SRIM程序介绍,outline,概括介绍SRIM,SRIM的应用,SRIM is a group of programs which calculate the stopping and range of ions into matter。 METHOD ：Using a full quantum mechanical treatment of ion-atom collisions.(SRIM always referes to the moving atom as an ion, and all target atoms as atoms),SRIM consists of two ma

2、in programs, and several special-purpose programs. SR(Tables of Stopping and Ranges of ions in simple targets). quickly creates Tables of the stopping and range of ions in matter over a wide band of ion energies. TRIM (the Transport of Ions in Matter) is a Monte-Carlo calculation which follows the i

3、on into the target, making detailed calculations of the energy transferred to every target atom collision. (multi-layer complex targets),蒙特卡罗模拟方法(M-C 方法) 通过计算机模拟跟踪一大批入射粒子的运动。粒子的位置、能量损失以及次级粒子的各种参数都在整个跟踪过程中存储下来, 最后得到各种所需物理量的期望值和相应的统计误差。在M-C 方法计算过程中采用连续慢化假设, 即入射离子与材料靶原子核的碰撞采用两体碰撞描述, 这一部分主要导致入射离子运动轨迹的曲折

4、, 能量损失来自于弹性能量损失部分, 而在两次两体碰撞之间认为入射离子与材料中的电子作用连续均匀地损失能量, 当入射为重离子时可认为在这期间入射离子作直线运动, 能量损失来自于非弹性能量损失部分。两次两体碰撞之间的距离以及碰撞后的参数通过随机抽样得到。,Monte-Carlo TRIM is very versatile: It will handle ion energies from 10 eV to 2 GeV/amu, and targets with up to eight layers, made up of twelve different elements. It will c

5、alculate both the final 3D distribution of the ions and also all kinetic phenomena associated with the ions energy loss: target damage, sputtering, ionization, and phonon production. All target atom cascades in the target are followed in detail. This program is more accurate in calculating ion range

6、s than the transport program used in the SR program to produce the range tables described above.,Stopping power:入射粒子在单位路程上损失的能量(-dE/dx). Range:入射粒子从进入靶起到停止点所通过的总的路程,称为射程. Projected Range: 以Rp表示射程在入射方向投影的长度,称作投影射程.,SRIM相关名词,左边的示意图是一个能量E,有入射角的入射粒子在物质中的轨迹。,是粒子在靶物质中所走过的路程， 是与入射方向平行的射程， 是与入射方向垂直的射程， 与入射表

7、面垂直的射程。,Ion :入射粒子 Atom :靶原子 Recoil atoms: 与入射粒子发生位移碰撞的反冲靶原子 Straggle: 射程是具有统计性质的,不完全一致,而有小的统计变化 Cascade:由于一个初级撞出原子而导至众多的原子发生位移的过程 Vacancy: 晶格中某个原子被移去后所形成的缺陷 Interstitial atoms:填隙原子是指在正常排列的晶格原子位置之间插入的多余原子. Backscattered Ions:从入射表面进来又从入射表面出去的入射粒子 Transmitted Ions:从入射表面进来从背面出去的入射粒子 Sputtered atoms:被入射粒

8、子碰撞而离开入射表面的靶原子,Displacement Collisions : The process where an energetic incident atom knocks a lattice atom off its site. Replacement Collisions : Atom sites with new atoms, identical to their original atom (this is discussed below). This is the only mechanism in which a vacancy may be re-occupied.,

9、Ionization : is energy loss to the target electrons. The electrons of the target absorb energy from the fast moving ions and recoil atoms, and then release it as heat if the target is a metal, or as phonons if the target is an insulator. Phonons : are energy stored in atomic vibrations in a crystal.

10、 Since all the atoms in a crystal are linked, when you start vibrating one of them, then all the others start vibrating also. This mass vibration is described as a phonon, since it is somewhat quantized (certain vibration modes are preferred).,Displacement Energy( ):发生原子位移所必须的最小能量。 Lattice Binding E

11、nergy( ): This is the energy that every recoiling target atoms loses when it leaves its lattice site and recoils in the target. Typically it is about 1 - 3 eV, but values are not known for most compounds. Surface Binding Energy( ) : This is the energy that target atoms must overcome to leave the sur

12、face of the target (units = eV). Final Energy(of a moving atom)( ):below which it is considered to be stopped . Final Energy is an energy below any of the above energies .,Assume: incident atom has atomic number , energy E . collision within the target with an atom of atomic number . After the colli

13、sion, the incident ion has energy and the struck atom has energy .,Displacements = Vacancies + Replacement Collisions Vacancies = Interstitials + (Atoms which leave the target volume),入射粒子产生级联碰撞的示意图,置换碰撞的示意图,溅射的示意图,SRIM的应用,入射粒子的数据,靶对象的数据,（元素，原子质量，入射粒子能量范围）,（元素，状态，原子质量，各成分所占比例）,简单的介绍,具体的数据,可以根据需要求得入射

14、粒子具体的能量对应的停止能量损失。,TRIM具体的输入表格和菜单,输入部分： 入射粒子Name Mass Energy Angle of Incidemce,靶Layer name Width Elements,计算损伤类型: Quick:采用 Kinchin-Pease模型来快速计算靶损伤情况 8层,12种元素，不关注靶损伤的详细情况或者溅射。 Full Damage Cascade:该项跟踪每一个反冲核直到它们的能量低于靶原子的位移阈能. 3层,4种元素。,输出窗口,TRIM的输出文件,TRIM Individual Ion Data Table A 1- RANGE_3D.TXT (Fi

15、nal 3D Ion Distribution) Table A 2 - BACKSCAT.TXT (Backscattered Ion Kinetics) Table A 3 - TRANSMIT.TXT (Transmitted Ion Kinetics) Table A 4 - SPUTTER.TXT (Sputtered Atom Kinetics) Table A 5 - TRIMOUT.TXT (Summary of Table A 2 - Table A 4) Table A 6 - COLLISON.TXT (Ion-Atom Collision Kinetics) Table

16、 A 7 - COLLISON.TXT (with Recoil Cascades) Table A 8 - COLLISON.TXT (with Kinchin-Pease Damage),Averaged TRIM Output Table A 9- TDATA.TXT (Summary of Calculation) Table A 10 - RANGE.TXT (Ion Range Distribution) Table A 11 - LATERAL.TXT (Ion Range Distribution) Table A 12 - IONIZ.TXT (Energy Loss to

17、Ionization) Table A 13 - PHONON.TXT (Energy Loss to Phonons) Table A 14 - VACANCY.TXT (Vacancy Production) Table A 15 - NOVAC.TXT (Replacement Collisions),TRIM的输出文件,1.（ Quick ）快速计算一定能量粒子打进靶材料中的深度,入射粒子在靶物质中的分布，粒子的电离效应能量损失，传递给反冲原子的能量，背散射粒子数和穿透粒子数。 2.（ Full ）计算入射粒子与靶原子的详细碰撞对靶物质的所有损伤。比如：溅射产额，入射粒子和反冲原子的能

18、量损失详细情况。,5.界面混合。,3.构建复杂的分层，做高能粒子探测器。,4.高能粒子慢化，根据入射粒子的能量和所需要的出射粒子的能量，精确的选定减速靶板的厚度。,6.可以根据右图的数据估计入射粒子对靶所造成的空缺损伤，考虑是否产生非晶形层。,7.利用右图提供的数据，根据入射剂量可估计入射粒子在靶材料中的密度分布。,还可以计算入射粒子不同能量不同入射角对靶的总损伤。,TRIM.DAT 可以算不同粒子，以不同的能量，从不同的位置，以不同的角度入射到靶中的情况。 A、在SRIM计算中，可以不受靶有多少层的限制 B、TRIM can be used to calculate the recoil cascades in solids by neutrons,electrons or photons(NEP particles). It uses as input the file TRIM.DAT which contains the kinetic information about target atoms which start recoil cascades. The fi