An XAS study of P clustering in Si

Generating p- or n- type semiconductors through the introduction of either phosphorus (P) or boron (B) has underpinned the semiconductor industry for decades. As device scaling moves towards 3D structures, it is necessary to increase doping levels by 2 -3 orders of magnitude to several at.%. This comes with new material challenges as the spatial distribution of the dopants is unknown and can form clusters which influences their functional properties. Here we will use X-ray absorption spectroscopy recorded at the P K edge to probe the local atomic arrangement, clustering, and bonding around the P atoms in samples with 4 at. % doping. Data will be correlated with density function theory (which suggests clusters may form around vacancies) as well as resistivity measurements. The X-ray data will be compared with real space images determined from 3D atom probe and be used to benchmark that new metrology and its analysis protocols.