Exploiting Fixed Charge to Control Schottky Barrier Height in Si|Al₂O₃|MoO_x – based Tunnel Diodes

Conference · Sun Jun 20 00:00:00 EDT 2021 · Conference Record of the IEEE Photovoltaic Specialists Conference

DOI:https://doi.org/10.1109/pvsc43889.2021.9519088· OSTI ID:1864563

Garland, Ben M. ^[1]; Davis, Benjamin E. ^[1]; Strandwitz, Nicholas C. ^[1]

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1. Lehigh Univ., Bethlehem, PA (United States)

The insertion of a tunneling atomic layer deposited (ALD) Al₂O₃ film between MoO_x and p-type Si has been studied to investigate Schottky barrier height tunability with varied negative fixed charge density. This work seeks to increase the hole-selectivity of MoO_x-based contacts through manipulation of interface fixed charge. Fixed charge density and interface trap state densities are determined as a function of alumina processing conditions in metal-oxide-semiconductor capacitors (MOSCAPs). Schottky barrier heights were determined from Mott-Schottky analysis of tunnel diodes. An alumina deposition temperature of 80°C and post-deposition annealing at 425°C yielded the highest magnitude of negative fixed charge density (-3.5 × 10¹² q . cm^–2). High deposition temperature and/or post-deposition annealing produced the lowest interface trap state density (1 × 10¹² eV ^-1. cm^–2). On p-type silicon, Schottky barrier height minimization was not clearly correlated with increasing fixed charge density. However, on n-type silicon, a significant increase in Schottky barrier height was evident (~0.8 eV to > 1 eV) and is attributed to the large negative fixed charge. Here, the findings from this work indicate that Schottky barrier height in carrier selective contacts can be tuned by electrostatic engineering of the SiO_x|Al₂O₃ interface.

• Research Organization: Lehigh Univ., Bethlehem, PA (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• DOE Contract Number: EE0008743
• OSTI ID: 1864563
• Journal Information: Conference Record of the IEEE Photovoltaic Specialists Conference, Conference: IEEE 48. Photovoltaic Specialists Conference (PVSC), Virtual, 20-25 Jun 2021; ISSN 0160-8371
• Publisher: IEEE
• Country of Publication: United States
• Language: English

Related Subjects

solar energy
photovoltaics
selective contacts
molybdenum oxide
Schottky barrier height
aluminum oxide
atomic layer deposition
fixed charge