用金属诱导准分子激光晶化法制备多晶硅薄膜

Preparation of Polycrystalline Silicon by Metal Induced-excimer Laser Annealing

提出了一种新的晶化方法———金属诱导准分子激光晶化法(MI ELA)。该方法在制备多晶硅(p Si)薄膜中包括两个步骤:第一步是用镍金属诱导方法(MIC)通过热退火形成NiSi2;第二步是再通过准分子激光退火方法(ELA)晶化形成p Si。通过用XRD、Raman与SEM测试,研究了p Si的结晶性和表面形貌特征。研究发现,MI ELA方法制备的p Si与传统的ELA方法和MIC方法相比在形貌上不一样,而且从XRD的特征峰强度可以看出在结晶度上有进一步提高。这个结果源于用MIC方法形成的且与c Si晶格匹配的NiSi2在ELA中起到晶核的作用。这种晶化方法说明,在ELA中,晶粒生长不再仅仅依赖于熔融非晶硅和氧化物表面上残存的随机的固体a Si作为成核媒介。这种方法不但可以提供晶粒稳定生长条件,而且也可能使获得更大晶粒粒度的激光晶化能量展宽。

A new crystallization method, the “metal induced excimer laser annealing”(MI ELA), has been developed. This method has two stePS involving the preparation of polycrystalline silicon film. One of which consists of a formation of NiSi 2 by the nickel metal induced crystallization (MIC), and the other consists of a formation of p Si by the excimer laser annealing (ELA). The crystallized fraction and morphology of p Si films were studied by testing with XRD, Raman and SEM. It is discovered that the p Si film has different morphology and has higher crystallization, showing in the intensity of cha racteristic peaks of XRD, than that prepared by the conventional ELA and MIC. It is resulted from the NiSi 2 which formed by MIC has the characteristics of crystal lattice match with c Si and can act as a seed for the following growth of polycrystalline silicon by the ELA. This method indicates that grains growth not only depends on remained solid a Si, as a media to form crystallized nuclei, distri buting randomly on surface between melted a Si and oxide. This method not only provides conditions of stable grains growth, but also makes it possible to increase the energy range of crystallized laser in order to gain bigger grains.