Diffusion of Phosphorus in Poly/Single Crystalline Silicon

Hideaki FUJIWARA  Hideharu NAGASAWA  Atsuhiro NISHIDA  Koji SUZUKI  Kazunobu MAMENO  Kiyoshi YONEDA  

IEICE TRANSACTIONS on Electronics   Vol.E75-C   No.9   pp.995-1000
Publication Date: 1992/09/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Silicon Devices and Materials)
ion implantation,  phosphorus,  diffusion,  polycrystalline silicon,  

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Diffusion of phosphorus impurities from a polycrystalline silicon films into a silicon substrate was investigated as a function of the mean concentration of phosphorus in a polycrystalline silicon film at the first diffusion stage. We presented that good control of the redistribution of implanted phosphorus impurities was possible by optimizing the normalized dose, which is the value: [the total dose of phosphorus impurities]/[the polycrystalline silicon film thickness], in the case of samples both with and without an arsenic doped layers. In the range where the normalized dose was less than 1.52.51020 cm-3, deeper junctions were formed in samples with an arsenic doped layer. In the range where the normalized dose was more than 1.52.51020 cm-3, however, deeper junctions were formed in samples without any arsenic doped layer rather than in samples with an arsenic doped layer. These results mean that formation of the junction in the device structure where a high concentration phosphorus doped polysilicon layer is stacked on to the high concentration arsenic layer embeded at the surface of the substrate can be restricted by optimizing the normalized dose. Moreover, a trade-off relationship between suppressing phosphorus diffusion and maintaining low contact resistance against normalized doses was also observed.