Nowadays, Neutron Transmutation Doping (NTD) of silicon ingots is successfully used to produce the n-type semiconductor. NTD’s main advantage, which is to say its uniform resistivity distribution, leads to semiconductor materials with fewer defects and, accordingly, better performance. Radial uniformity usually is achieved by rotating the ingot during irradiation. However, due to neutron attenuation, the neutron reaction rate in the ingot’s center region generally is lower than in the outer region. Such radial non-uniformity becomes severe when the diameter of the ingot is larger, or when materials with a high-neutron-reaction cross-section are used. In this study, a slit method to selectively shield neutrons that react with the ingot’s outer region and increase radial uniformity thereby was devised and herein is proposed. Dark matter (DM), graphite, stainless steel (SS) and borated stainless steel (BSS) were considered as shielding materials in a Monte Carlo-simulation-based evaluation of the radial uniformity of a Silicon Carbide (SiC) ingot. In the case of DM, the relative reaction rate at the center region of the ingot was increased; graphite did not enhance the radial uniformity; for both SS and BSS, the radial uniformity was under 1% with the optimized slot size. Therefore, it is expected that if the NTD technique is used in concert with the proposed slit method, semiconductors of exceedingly uniform dopant distribution can be produced.

如今，硅锭的中子嬗变掺杂 (NTD) 已成功用于生产 n 型半导体。NTD 的主要优势，即其均匀的电阻率分布，导致半导体材料缺陷更少，因此性能更好。径向均匀性通常是通过在辐照过程中旋转锭来实现的。然而，由于中子衰减，铸锭中心区域的中子反应速率通常低于外部区域。当铸锭直径较大时，或使用具有高中子反应截面的材料时，这种径向不均匀性变得严重。在这项研究中，设计并提出了一种狭缝方法，以选择性地屏蔽与铸锭外部区域发生反应的中子，从而增加径向均匀性。暗物质（DM），在基于蒙特卡罗模拟的碳化硅 (SiC) 锭径向均匀性评估中，石墨、不锈钢 (SS) 和硼化不锈钢 (BSS) 被视为屏蔽材料。在DM的情况下，铸锭中心区域的相对反应速率增加；石墨没有增强径向均匀性；对于 SS 和 BSS，使用优化的槽尺寸，径向均匀度均低于 1%。因此，预计如果 NTD 技术与所提出的狭缝方法一起使用，则可以生产出掺杂剂分布非常均匀的半导体。提高了铸锭中心区域的相对反应速率；石墨没有增强径向均匀性；对于 SS 和 BSS，使用优化的槽尺寸，径向均匀度均低于 1%。因此，预计如果 NTD 技术与所提出的狭缝方法一起使用，则可以生产出掺杂剂分布非常均匀的半导体。提高了铸锭中心区域的相对反应速率；石墨没有增强径向均匀性；对于 SS 和 BSS，使用优化的槽尺寸，径向均匀度均低于 1%。因此，预计如果 NTD 技术与所提出的狭缝方法一起使用，则可以生产出掺杂剂分布非常均匀的半导体。