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Probe assisted localized doping of aluminum into silicon substrates.

Authors :
Ahn JJ
Solares SD
You L
Noh H
Kopanski J
Obeng Y
Source :
Journal of applied physics [J Appl Phys] 2019; Vol. 125 (7).
Publication Year :
2019

Abstract

Precise control of dopant placement is crucial for the reproducible, and reliable, nanoscale semiconductor device fabrication. In this paper, we demonstrate an atomic force microscopy (AFM) probe assisted localized doping of aluminum into an n-type silicon (100) wafer to generate nanoscale counter-doped junctions within two nanometers of the silicon-air interface. The local doping results in changes in electrostatic potential, which are reported as contact potential difference, with nanoscale spatial resolution. In contrast to the literature where nano-mechanical defects in, or contaminants on, silicon substrates can result in measurable changes in the chemical potential of the near-surface, additional thermal treatment was needed to electrically activate the aluminum dopants in our current work. Unfortunately, the thermal activation step also caused the dopants to diffuse and geometric distortions in the doped area, i.e., broadening and blurring of the electrically distinct areas. The results from optimization efforts show that the "active" dopant concentration depended primarily on the thermal anneal temperature; additional AFM-tip dwell time during the aluminum implantation step had no meaningful impact on the electrical activity of the doped sites.

Details

Language :
English
ISSN :
0021-8979
Volume :
125
Issue :
7
Database :
MEDLINE
Journal :
Journal of applied physics
Publication Type :
Academic Journal
Accession number :
39444421
Full Text :
https://doi.org/10.1063/1.5065385