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Probe assisted localized doping of aluminum into silicon substrates



Jungjoon Ahn, Santiago D. Solares, Lin You, Hanaul Noh, Joseph J. Kopanski, Yaw S. Obeng


In this paper, we demonstrate AFM probe assisted deterministic doping (PADD) of Al into an n- type Si (100) wafer, to generate nanoscale counter-doped junctions with a few nanometers depth from Si surface. The local electrical potential changes resulting from the PADD process, reported as Contact Potential Difference (CPD), were investigated with a scanning Kelvin probe microscope (SKPM). Comparison of the CPD values before and after the thermal annealing of PADD- processed area shows that the Al dopants required additional thermal treatment in order to become electrically active (to overcome the activation energy and become electrically active). However, the thermal activation step also caused the dopants to diffuse further into Si substrate, which results the expansion of deterministically doped sites. Furthermore, the “active” dopant concentration depended primarily on the thermal anneal temperature, while the additional AFM-tip dwell time during the Al implantation step had no material impact on the doping process and the resultant electrical activity of the doped sites
Journal of Applied Physics


deterministic doping, silicon, aluminum doping, scanning Kelvin probe microscope (SKPM)
Created February 20, 2019, Updated February 21, 2019