【作者】 王岩；

【导师】 齐民； 李斗星；

【作者基本信息】 大连理工大学 ， 材料学， 2008， 博士

【摘要】 离子注入作为一种高效的材料表面改性技术，被广泛地应用于改善材料表面的物理、化学和机械性能。离子注入α-Al₂O₃陶瓷具有优越的力学性能，所以常常被用做结构材料。近年来，人们还发现Fe离子注入α-Al₂O₃陶瓷具有优越的磁学性能，将来可能被用做新一代的数据存储介质。另外，离子注入技术还用来制备CoSi₂埋层，这种金属硅化物埋层有望成为集成电路中新一代的欧姆接触和互联引线。但是对于注入后的α-Al₂O₃陶瓷和单晶硅样品，目前在微结构上的认识还是非常有限的，而材料的微结构决定材料的性能和应用，所以对离子注入样品的微结构进行深入地研究是非常有必要。本文利用透射电镜对Fe注入α-Al₂O₃原始注入态、还原气氛下退火态和氧化气氛下退火态的微结构进行了研究，另外还对Co注入单晶硅原始注入态和真空退火态的微结构进行了研究。得到的主要结论如下：在低注量(1×10¹⁶ions／cm²)Fe注入α-Al₂O₃单晶原始注入态样品中，没有析出α-Fe颗粒，注入区存在着高浓度晶体缺陷，但α-Al₂O₃基体仍保持单晶结构。在高注量(1×10¹⁷ions／cm²)样品中，析出了1-3nm的小颗粒。结合McHargue等人穆斯堡尔谱分析结果，我们认为析出相是α-Fe颗粒。注入区存在着浓度更高的晶体缺陷，α-Al₂O₃基体仍保持单晶结构。对Fe注入α-Al₂O₃单晶在还原气氛下进行退火处理后，α-Al₂O₃基体中生成α-Fe颗粒。α-Fe颗粒与α-Al₂O₃基体具有如下的取向关系：（111）_α-Fe)//（0001）_sapphire和[1（?）0]_α-Fe//[11（?）0]_sapphire这与Ohkubo等人的实验结果是一致的。其中，少量的α-Fe颗粒偏离该取向关系，最大偏离角小于3°。大的α-Fe颗粒具有两种典型的轮廓：一些α-Fe颗粒的轮廓是由α-Al₂O₃（0001）、{11（?）0)和{2（?）3}晶面构成；另一些α-Fe颗粒的轮廓是由α-Al₂O₃（0001）、{11（?）0}、{2（?）3)和{2（?）}晶面构成。利用倒空间近重位点阵分析表明，在α-Fe和α-Al₂O₃体系中，上式所表示的取向关系是最有利的，而该体系中观察到的另一取向关系：（110）_α-Fe//（0001）_sapphire和<111>_α-Fe//<5（?）0>_sapphire被证明是次有利取向关系。对Fe注入α-Al₂O₃单晶在氧化气氛下进行退火处理后，在α-Al₂O₃基体表面出现了两种析出相：α-Fe₂O₃析出相和尖晶石析出相。α-Fe₂O₃析出相与α-Al₂O₃基体具有下面的取向关系：[0001]_α-Fe2O3//[0001]_sapphire和（11（?）0）_α-Fe2O3//（11（?）0）_sapphire岛状α-Fe₂O₃析出相的三维轮廓是由两个α-Fe₂O₃（0001）晶面和六个α-Fe₂O₃{10（?）2}晶面构成的。α-Fe₂O₃析出相与α-Al₂O₃基体的界面属于半共格界面。沿α-Al₂O₃[（?）100]晶向观察，α-Fe₂O₃（0001）／α-Al₂O₃（0001）界面失配位错的柏氏矢量分量是1／6[11（?）0]_sapphire。沿α-Al₂O₃[11（?）0]晶向观察，界面失配位错的柏氏矢量分量是1／2[（?）100]_sapphire。尖晶石析出相与α-Al₂O₃基体具有两种取向关系，其中一种是尖晶石相与α-Al₂O₃之间普遍存在的取向关系：（111）_spinel//（0001）_sapphire和[11（?）]_spinel//[11（?）0]_sapphire另外一种是在spinel／α-Al₂O₃体系中首次被发现的取向关系：（11（?））_spinel//（0001）_sapphire和[111]_spinel//[11（?）0]_sapphire尖晶石析出相与α-Al₂O₃基体的界面属于非共格界面。在Co注入单晶硅原始注入态样品中观察到了CoSi₂析出相，并且CoSi₂析出相与单晶硅具有下面的取向关系：[110]_CoSi2／／[110]_Si和（2（?）0）_CoSi2//（2（?）O）_SiCoSi₂析出相六边形轮廓的边平行于Si{001}晶面和Si{111}晶面。同时在注入末端区域观察到了大量的{113}缺陷及缺陷初始生成阶段的高分辨像。退火过程使得原始注入态下大量的小CoSi₂析出相合并成大的CoSi₂析出相，没有形成连续的CoSi₂埋层。更多还原

【Abstract】 Ion implantation is an effective technique to modify the physical, chemical and mechanical properties of material surface layer. Ion-implanted sapphire has excellent mechanical properties, which often serves as structural ceramic. In recent years, Fe-implanted sapphire has been found to have excellent magnetic properties, which may serve as data-storage medium in the future. Ion implantation has also been used to form buried CoSi₂ layers, which may serve as a new generation interconnect leading wire in integrated circuit in the future. But the microstructure of ion-implanted sapphire and silicon has been understood not clearly enough at present. Since microstructures of materials decide properties of materials, it is necessary to investigate the microstructure of ion-implanted samples deeply.Microstructure of Fe-implanted sapphire and Co-implanted silicon （as-implanted samples and annealing samples） is investigated by transmission electron microscopy. The primary conclusions are listed as follows:Noα-Fe particles precipitate in sapphire implanted with 1×10¹⁶ Fe ions/cm² and there is high-density defect in implanted zone, but the implanted layer has the crystalline nature. In sapphire implanted with 1×10¹⁷ Fe ions/cm² there are many small particles about 1-3 nm, which should beα-Fe considering the Mossbauer results, and the defect-rich implanted layer still has the crystalline nature.In sapphire implanted with iron and annealed in a reducing atmosphere the implanted Fe ions precipitate as theα-Fe particles. Most of theα-Fe particles have the orientation relationship （OR） of （111）_α-Fe//（0001）_sapphire and [1（?）0]_α-Fe//[11 （?） 0]_sapphire with sapphire, which was also discovered by Ohkubo et al. Only a small quantity of theα-Fe particles have the deviation from this OR and the maximum deviation is less than 3°. The largeα-Fe particles clearly have faceted outlines. Two typical outlines have been observed. One outline consists of {0001}, {11（?） 0} and {2（?）3} of sapphire. The other outline consists of {0001}, {11（?） 0}, {2（?）3} and {2（?）} of sapphire. The coincidence of reciprocal lattice points method has been utilized to confirm that the OR above is preferred in theα-Fe/sapphire system and another OR of （110）_α-Fe//（0001）_sapphire and <111>_α-Fe//<5（?）0>_sapphire reported before is the secondary preferred orientation.In sapphire implanted with iron and annealed in an oxidizing atmosphere the implanted Fe ions precipitate asα-Fe₂O₃ islands and spinel islands on the specimen surface. Theα-Fe₂O₃ islands have the orientation relationship of [0001]_α-Fe2O3//[0001]_sapphire and （11（?）0）_α-Fe2O3// （11（?） 0）_sapphire with sapphire. The typical outline ofα-Fe₂O₃ islands consists of two （0001） and six {10（?）2} planes ofα-Fe₂O₃. The interfaces betweenα-Fe₂O₃ islands and sapphire are, semicoherent. When imaged along the [（?）100]_sapPhire direction, the projected Burgers vector is determined to be 1/6[11 （?） 0]_sapphire. When imaged along the [11 （?） 0]_sapPhire direction, the projected Burgers vector is determined to be 1/2[（?）100]sapphire.Two ORs between the spinel islands and sapphire substrate have been discovered. One is （111）_spinei // （0001）_sapphire and [11（?） ]_spinei // [11（?） 0]_sapphire, which is consistent with the most common OR between spinel and sapphire. The other is （11（?） ）_spinel // （0001）_sapphire and [111]_spinel//[11（?） 0]_sapphire, which is discovered for the first time. The interfaces between the spinel islands and sapphire substrate are an incoherent interface.In silicon implanted with Co there are many small CoSi₂ precipitates and the CoSi₂ precipitates have the orientation relationship of [110]_CoSi2//[110]_Si and （2（?） 0）_CoSi2//（2（?） 0）_Si with silicon substrate. The outline of hexagonal CoSi₂ precipitates consists of {001} and {1（?）1} planes of silicon. At the same time there are many rod-like {113} defects and some Si interstitials clusters corresponding to the initial configuration of {113} defects at the end-of-range damage zone. With annealing in vacuum the small CoSi₂ precipitates don’t form the continuous buried CoSi₂ layers, but form large CoSi₂ precipitates.更多还原