Investigating the regrowth surface of Si:P δ-layers toward vertically stacked three dimensional devices

We investigate the surface quality of encapsulated Si:P $\delta$ -layers for the fabrication of multilayer devices with the potential to create architectures with sub 20 nm resolution in all three spatial dimensions. We use scanning tunneling microscopy to investigate how the dopant incorporation chemistry of the first active layer strongly affects the quality of the Si encapsulation which serves as the regrowth interface for the second active layer. Low temperature Hall measurements of the encapsulated layers indicate full dopant activation for incorporation temperatures between $250–750°\text{C}$ with 20% higher carrier densities than previously observed.