【作者】 李恒；

【导师】 龚敏；

【作者基本信息】 四川大学 ， 凝聚态物理， 2003， 硕士

【摘要】 在集成电路和半导体器件的生产过程中，许多工序都可能使硅片受到金属的污染。由于金属杂质原子扩散并沉积在器件的有源区，会造成诸如：反向漏电流较大，反向击穿电压是软击穿等有害的影响。所以需要减小有源区中金属杂质的浓度，通常采用吸除的方法把金属杂质从器件有源区吸收到有源区之外预先形成的Sink(陷阱)中。 我们注意到，在研究氢、氦离子注入诱生微孔的吸除作用时多以对金杂质的吸除效果来对吸除工艺进行评估，因此本文对微孔吸除机理、金在硅中的扩散和分布以及半导体中离子注入的特点进行了描述。 在本工作中，通过原子力显微镜(AFM)观测到注氦抛光面经热处理后，氦气膨胀将背表面处硅薄层顶出形成的“凸包”，而在未经注氦的参比样品中则无此图像出现，因此我们定性认为本研究中注入硅中的氦，在热处理过程中的确形成了微孔。 本研究主要采用掺金的双面抛光片和单面抛光片制成的硅平面二极管为研究样品，利用二极管反向漏电流密度J_r的变化，着重研究吸除热处理过程对注氦诱生微孔吸除效果的影响，得到微孔对实验样品中金杂质的较合适的吸除热处理温度(800℃)和时间(6小时)；而且，不仅证实注氦诱生微孔在双面抛光片制成的样品中能有效的吸除金杂质(吸除热处理后J_r减小一个量级以上)；并首次观测到在粗糙背面注氦后形成的微孔对金杂质也有良好的吸除作用。由于实际的集成电路和分离器件都是做在单面抛光片上的，这一结果对将微孔吸除技术用于实际器件的生产过程具有较重要的参考价值。 本文还对实验样品中存在的氧沉积、晶格损伤对金杂质的吸除效果，与注氦诱生微孔的吸杂效果进行了比较和讨论，进一步证实了注氦诱生微孔吸除金杂质的均匀性，并加深了对微孔吸除机理的理解。更多还原

【Abstract】 Metal contamination in a silicon wafer is unavoidable during the many steps required for the fabrication of microelectronics devices. High leakage currents and soft reverse current-voltage characteristics are some of the detrimental effects produced by the metal atoms dissolved in the silicon matrix. Gettering procedures can reduce metal contamination. Many gettering techniques have been widely studied to overcome this problem by removing metal impurities from active regions of device.One new gettering method that has recently received growing interest is the use of nanocavities resulting from helium or hydrogen implantation. The gettering processes usually are estimated by gettering of Au to nanocavity in silicon. In this paper, the characteristics of nanocavity gettering mechanism, diffusion and distributing of aurum and ion implantation in silicon were described.In this work, many bumps on the polishing surface of the silicon, after a He+ impantation in and subsequently a hot-treatment, were observed using atomic force microscope(AFM). But this phenomena could not be observed without He+ impantation.The diodes manufactured using back-side and double-side Au-doped waferswere studied in this work. The effects of the nanocavity-gettering technique were monitored by the leakage current. The experimental results showed that the thermal treatment of the gettering-process was very important to the gettering efficiency. After gettering thermal treatment at 800 for 6 hours, the leakage-current density of the diodes were decreased. The experiments also showed that the gettering efficiency of the diods with a rough-back-side were a little bit better than those with a polished-back-side for the first time. In addition, integrated circuits and semiconductor devices are generally made with single-side polished wafers, therefore the results of this work indicate that nanocavity-gettering technique is practical in manufacture of devices. Finally, the gettering uniformity is demonstrated directly on samples.The gettering results of Au to oxygen intrinsic precipitation and to the nanocavity formed by helium ion implantation were compared and discussed in this paper.更多还原