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高溶点金属及其硅化物电阻率低、化学稳定性和热稳定性好,且不受电迁移的影响,故适用于高集成度元件的制作。而用激光为工具,制备高溶点金属及其硅化物易于实现半导体表面的局部加热,且减少杂质。本文报道用 CO_2激光诱导氧化锰的铝还原反应,在单晶硅表面得到厚度为5～10μm 的锰薄层。实验中,基片为〈100〉切割的单晶硅,工作物质为化学纯的 MnCO_3和 Al 粉末。将这二种粉末按化学计量配比,充分混和后置于硅表面,厚度为1毫米。激光器为功率20W 的封离型 CO_2激光器,光斑直径4毫米,扫描速度1毫米/分。激光照射期间,用光学高温计测量温度。激光照射首先引起 MnCO_3热分解,生成氧化锰。在激光作用区域,温度可达1200℃。化学分析表明:热分解收到的混合物中含有98～99％的 Mn_3O_4和 Mn_2O_3。激光又引起强烈的放热反应,由于激光作用区温度很高,更加强了这一反应。用电子显微镜研究表明:实验条件下温度达1970℃,硅表面熔融,从而使锰原子向硅扩散,大大提高了薄膜对硅表面的粘附强度。激光照射后,用刷子将样品刷干净,并用酒精仔细清洗以去除渣屑及未反应的粉末。样品在照射前后均用扫描式立体电子显微镜进行分析,用二次电子获得显微图象,并测成分。结果表明:样品的表面以及组份均发生了变化。文中给出了硅表面之锰薄层的扫描电镜照片。薄层较均匀,含99％锰以及1％的杂质,该杂质系 MnCO_3粉末中原有的杂质,而不是 Al 或 C,另外,文中又给出来抛光单晶硅表面形貌在激光照射前后的变化的照片。激光照射过的区域相当光滑,说明由于氧化锰与铝反应时产生的高温使硅熔融并重结晶。运用铝与氧化锰的放热反应在硅表面制备锰薄膜,可提高纯度,并可运用小功率激光来进行制备。作进一步实验还可得到 Ni、Mo、W 等薄膜,这些金属的氧化物对10.6 μm CO_2激光均有良好吸收。
High melting point metal and its silicide low resistivity, chemical stability and thermal stability, and not affected by electromigration, it is suitable for the production of highly integrated components. The use of laser as a tool to prepare high melting point metal and its silicide easy to achieve local heating of the semiconductor surface, and reduce impurities. This paper reports the aluminum reduction reaction of manganese oxide induced by CO2 laser to obtain a thin layer of manganese with a thickness of 5 ~ 10μm on the surface of monocrystalline silicon. Experiments, the substrate is <100> cut monocrystalline silicon, working substance is chemically pure MnCO_3 and Al powder. The two kinds of powder stoichiometric ratio, fully mixed and placed on the silicon surface, a thickness of 1 mm. Laser power 20W sealed off type CO_2 laser spot diameter of 4 mm, the scanning speed of 1 mm / min. During laser irradiation, the temperature was measured with an optical pyrometer. Laser irradiation first caused MnCO_3 thermal decomposition, generating manganese oxide. In the laser action area, the temperature can reach 1200 ℃. Chemical analysis shows that: the mixture received by thermal decomposition contains 98-99% Mn 3 O 4 and Mn 2 O 3. The laser also caused a strong exothermic reaction, due to the high temperature of the laser role of the region, even stronger this response. Electron microscopy studies show that: under the experimental conditions, the temperature reaches up to 1970 ℃, the silicon surface is melted, so that the manganese atoms are diffused into the silicon, which greatly improves the adhesion strength of the film to the silicon surface. After the laser is irradiated, the sample brush is brushed with a brush and carefully washed with alcohol to remove dross and unreacted powder. Samples before and after irradiation were analyzed by scanning electron microscopy, microscopy images obtained with secondary electrons, and test scores. The results show that the sample surface and components have changed. The paper gives a scanning electron micrograph of a thin layer of manganese on a silicon surface. The thin layer is more uniform, containing 99% manganese and 1% impurities, the impurities of MnCO_3 powder in the original impurities, rather than Al or C, In addition, the paper gives the surface morphology of polished single crystal before and after laser irradiation changes Photo. The area irradiated by the laser is quite smooth, indicating that the silicon is melted and recrystallized due to the high temperature generated when the manganese oxide reacts with the aluminum. The use of aluminum and manganese oxide exothermic reaction in the preparation of manganese thin film on the silicon surface can improve the purity, and the use of low-power laser can be prepared. For further experiments, Ni, Mo, W and other thin films were also obtained, and the oxides of these metals all showed good absorption for the 10.6 μm CO 2 laser.