Enhanced Atomic Precision Fabrication by Adsorption of Phosphine into Engineered Dangling Bonds on H–Si Using STM and DFT
Jonathan Wyrick, Xiqiao Wang, Pradeep Namboodiri, Ranjit Kashid, Fan Fei, Joseph Fox, Richard M. Silver
Doping of Si using the scanning probe technique of hydrogen depassivation lithography has been shown to enable placing and positioning small numbers of P atoms with nanometer accuracy. Several groups have now used this capability to build devices that exhibit desired quantum behavior determined by their atomistic details. What remains elusive, however, is the ability to control the precise number of atoms placed at a chosen site with 100% yield, thereby limiting the complexity and degree of perfection achievable. As an important step towards controlling dopant number, we explore the adsorption of the P precursor molecule, phosphine, into atomically perfect dangling bond patches consisting of 3 adjacent Si dimers along a dimer row. We identify the adsorption products by generating and comparing to a catalog of simulated scanning tunneling microscope images, explore prospects for atomic manipulation after adsorption, and follow up with incorporation of P into the substrate. Imaging after incorporation suggests that, for saturation dosed perfect lithographic patches, controllable placement of single atoms may have higher yield than previously expected. Based on the observations made in this study, we propose approaches that can be used to fabricate devices where it is ensured that each site of interest has exactly one P atom.
, Wang, X.
, Namboodiri, P.
, Kashid, R.
, Fei, F.
, Fox, J.
and Silver, R.
Enhanced Atomic Precision Fabrication by Adsorption of Phosphine into Engineered Dangling Bonds on H–Si Using STM and DFT, ACS Nano, [online], https://doi.org/10.1021/acsnano.2c08162, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=933497
(Accessed December 10, 2023)