Fabrication of p-β-Fe _1-xMn _xSi ₂/n-Si heterostructure diode and their electrical and optical properties

We report on the fabrication of p-type β-FeSi ₂ layers on n-type Si(100) substrates and the investigation of their p-n diode characteristics. Since our undoped β-FeSi ₂ layers have typically shown n-type conductivity, the p-type layers were formed by the introduction of Mn impurity into β-FeSi ₂ layers using two types of doping methods; one is an Electron-Beam-Deposition (EBD) procedure of Fe _1-XMn _XSi ₂(X < approximately 0.1) at room temperature and subsequent annealing at 900 °C for 1-120 min, where FeSi ₂ ingots added with Mn (approximately 10 %) were used as starting materials. The other is a ⁵⁵Mn ⁺-implantation into β-FeSi ₂ layers formed by EBD and subsequent annealing at 850 °C for 1-120 min. From van der Pauw measurements, p-type β-Fe _1-XMn _XSi ₂ layers with the resistivity of 0.0036-0.031 Ω·cm and hole mobility of 11.9-89.0 cm ²/V·sec were found to be successfully formed on n-Si substrates by both doping methods. The p-n diode characteristics of these heterostructure diodes were investigated by I-V and C-V measurements. The results indicate that the carrier distribution does not agree with either ideal one-side step or one-side slop junctions, although optical transmittance and reflectance measurements indicate that the silicide/Si interface is of good quality.