二氧化硅纳米球对硼酸源扩散形成p＋硅层性能的影响

Influence of SiO_2 Nanosphere on the Performance of p^+ Layer Formed by B Diffusion from Boric Acid Solution

为了提高B扩散掺杂层的性能,提出了用含有二氧化硅纳米球的硼酸溶液作为硼源对硅片进行扩散的方法。采用扫描电子显微镜、四探针和少子寿命测试等技术研究了SiO_2纳米球对硼酸源扩散形成p^+硅层性能的影响。综合分析发现,与未添加SiO_2纳米球相比,扩散后生成的富硼层厚度明显减小,由130nm降低到15nm;同时,扩散的均匀性由88.17%提高到了96.79%。此外,添加SiO_2纳米球进行扩散后p-n结深有所减小,少数载流子寿命明显提高。研究结果表明,SiO_2纳米球可以显著提高液态硼源扩散掺杂形成p^+硅层的性能。

In order to improve the quality of B doped layer by diffusion, a novel boron source mixed with SiO2 nanosphere was introduced. Scanning electronic microscopy, four probe method and minority carrier lifetime measurement were adopted to study the influence of SiO2 nanosphere on the performance of p＋ layer formed by B diffusion from boric acid solution. It was found that the thickness of boron rich layer （BRL） decreased from 130 nm to 15 nm compared with that produced without addition of SiOz nano- sphere. At the same time, the uniformity of diffusion increased from 88. 17% to 96. 79%. In addition, junction depth decreased slightly and minority carrier lifetime in the samples increased apparently after using mixed boric acid solution with SiO2 nanosphere. All the results above indicated that SiO2 nanosphere could evidently enhance the property of the p＋ layer formed by liquid B source diffusion from boric acid solution.