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Title: In situ measurement of fixed charge evolution at silicon surfaces during atomic layer deposition

Interfacial fixed charge or interfacial dipoles are present at many semiconductor-dielectric interfaces and have important effects upon device behavior, yet the chemical origins of these electrostatic phenomena are not fully understood. We report the measurement of changes in Si channel conduction in situ during atomic layer deposition (ALD) of aluminum oxide using trimethylaluminum and water to probe changes in surface electrostatics. Current-voltage data were acquired continually before, during, and after the self-limiting chemical reactions that result in film growth. Our measurements indicated an increase in conductance on p-type samples with p{sup +} ohmic contacts and a decrease in conductance on analogous n-type samples. Further, p{sup +} contacted samples with n-type channels exhibited an increase in measured current and n{sup +} contacted p-type samples exhibited a decrease in current under applied voltage. Device physics simulations, where a fixed surface charge was parameterized on the channel surface, connect the surface charge to changes in current-voltage behavior. The simulations and analogous analytical relationships for near-surface conductance were used to explain the experimental results. Specifically, the changes in current-voltage behavior can be attributed to the formation of a fixed negative charge or the modification of a surface dipole upon chemisorption of trimethylaluminum. These measurementsmore » allow for the observation of fixed charge or dipole formation during ALD and provide further insight into the electrostatic behavior at semiconductor-dielectric interfaces during film nucleation.« less
Authors:
; ;  [1]
  1. Department of Materials Science and Engineering and Center for Advanced Materials and Nanotechnology, Lehigh University, Bethlehem, Pennsylvania 18015 (United States)
Publication Date:
OSTI Identifier:
22412596
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM OXIDES; CHEMISORPTION; DIELECTRIC MATERIALS; DIPOLES; ELECTRIC CONDUCTIVITY; ELECTRIC POTENTIAL; ELECTROSTATICS; FILMS; INTERFACES; NUCLEATION; PROBES; P-TYPE CONDUCTORS; SILICON; SURFACES