Search

For scaling of bulk Si Fin field-effect transistor (FinFET), suppression of short-channel effects is required without ON-state current degradation. In this letter, solid-source doping for channel doping using 1-nm phosphosilicate glass was demonstrated on both p-type (100) Si substrate and p-type bulk Si FinFET. The profile of phosphorus in p-type (100) Si substrate was analyzed by secondary ion mass spectrometry and it was diffused deeper with higher thermal budget of anneal. Fabricated bulk Si FinFETs with using 1-nm phosphosilicate glass showed threshold voltage shift with several anneals at 1- $\mu \text{m}$ and 70-nm gate lengths. Hole mobility at 1- $\mu \text{m}$ gate length and transconductance at 70-nm gate length were also reduced due to increase in impurity concentration of phosphorus diffused by anneals into Fins. Phosphorus diffusion into Fins with using 1-nm phosphosilicate glass was investigated and phosphorus behavior after anneal was clarified by electrical data of p-type bulk Si FinFETs.

In recent years Solid Source Doping (SSD) has been considered as a viable option in fabricating advanced CMOS devices [1], especially for forming shallow and highly doped junctions for source drain extensions (SDE) while minimizing the damage to the devices [2]. Current scaled devices require diffusion control in the nanometer range in order to form shallow SDEs using SSD. Additionally, high doping concentrations are needed to lower the resistivity (see Fig. 1).