Investigating the surface quality and confinement of Si:P image at different growth temperatures

We use scanning tunneling microscopy and low temperature magnetotransport measurements to study the effect of encapsulation temperature on phosphorus δ-layers in silicon. In particular we examine the quality of the resultant surface after encapsulation for the fabrication of three dimensional devices. Dopants were overgrown with 25 nm of silicon at temperatures between 250 and 300 °C. Electrical measurements show that 100% activation of dopants was obtained for View the MathML source encapsulation. However, dopant activation reduced to 54% as the growth temperature was increased to View the MathML source. Moreover we find that encapsulating above View the MathML source leads to dopant segregation that deactivates and broadens the δ-layer, without any substantial improvement in the quality of the regrowth surface.