Measurement of phosphorus segregation in silicon at the atomic-scale using STM

In order to fabricate precise atomic-scale devices in silicon using a combination of scanning tunnelling microscopy (STM) and molecular beam epitaxy it is necessary to minimize the segregation/diffusion of dopant atoms during silicon encapsulation. We characterize the surface segregation/diffusion of phosphorus atoms from a $\delta$-doped layer in silicon after encapsulation at 250$^{\circ}$C and room temperature using secondary ion mass spectrometry (SIMS), Auger electron spectroscopy (AES), and STM. We show that the surface phosphorus density can be reduced to a few percent of the initial $\delta$-doped density if the phosphorus atoms are encapsulated with 5 or 10 monolayers of epitaxial silicon at room temperature. We highlight the limitations of SIMS and AES to determine phosphorus segregation at the atomic-scale and the advantage of using STM directly

Wilhem Kellerman (1908-1980)

Bilger A., Butters Gerhard, Krapoth H., Mölk Ulrich. Wilhem Kellerman (1908-1980). In: Cahiers de civilisation médiévale, 23e année (n°89), Janvier-mars 1980. pp. 77-78