2DEGs and FETs based on perovskite oxide semiconductors and dielectrics
ORAL · Invited
Abstract
The perovskite oxide stannate (ASnO3, A=Ba, Sr, Ca) system exhibits wide to ultrawide bandgap (3.0~4.6 eV), high mobility at room temperature and stable surface/interface behavior. Such properties can provide a new platform to put together many interesting properties of various perovskite oxides and create new functions that have not been possible before.
In combination with the lattice matched polar perovskite oxide LaInO3, a high density 2DEG can be created. Its formation mechanism, namely the “interface polarization” created by the inversion symmetry breaking at the orthorhombic LaInO3 and the cubic BaSnO3 interface, is a very unique feature of perovskite oxides. We have recently achieved a mobility of 2,000 cm2/V·sec by electric-double-layer gating.
When combined with the lattice matched and highly insulating SrHfO3, a complex multilayer structure such as double-gate FETs can be demonstrated. Such complex structure is possible due to the existence of degenerately doped La-doped BaSnO3 as the electrodes. In addition, the large conduction band offset between the BaSnO3 and SrHfO3 also enables a unique 2DEG formation at the non-polar interface of SrHfO3/BaSnO3.
In combination with a new high-k perovskite dielectric oxide BaHf0.6Ti0.4O3 as a gate oxide, 2D charge density larger than 1014 cm-2 can be modulated by field effect. We have created a new perovskite dielectric oxide BaHf0.6Ti0.4O3 which exhibits both a high-k dielectric constant and a high dielectric strength (low leakage current and high breakdown field). Recently, polycrystalline BaHf0.6Ti0.4O3 has been successfully integrated as a superb gate oxide for GaN systems.
When a lattice matched ferroelectric PbZr0.7Ti0.3O3 is used as a gate oxide, ferroelectric FET can be realized. The structurally perfect interface at PbZr0.7Ti0.3O3/BaSnO3 can work as a model system to study the switching properties of ferroelectric/semiconductor structure. We will discuss the implications of the ferroelectric and semiconducting material parameters on the switching performance.
Lastly, using SrSnO3 with 4.6 eV bandgap, we demonstrated DUV-transparent FETs by integrating with the ultrawide bandgap LaScO3 as the gate oxide. The resultant device shows a high field effect mobility, a large on/off ratio, and high optical transmittance larger than 75% at 300 nm.
In combination with the lattice matched polar perovskite oxide LaInO3, a high density 2DEG can be created. Its formation mechanism, namely the “interface polarization” created by the inversion symmetry breaking at the orthorhombic LaInO3 and the cubic BaSnO3 interface, is a very unique feature of perovskite oxides. We have recently achieved a mobility of 2,000 cm2/V·sec by electric-double-layer gating.
When combined with the lattice matched and highly insulating SrHfO3, a complex multilayer structure such as double-gate FETs can be demonstrated. Such complex structure is possible due to the existence of degenerately doped La-doped BaSnO3 as the electrodes. In addition, the large conduction band offset between the BaSnO3 and SrHfO3 also enables a unique 2DEG formation at the non-polar interface of SrHfO3/BaSnO3.
In combination with a new high-k perovskite dielectric oxide BaHf0.6Ti0.4O3 as a gate oxide, 2D charge density larger than 1014 cm-2 can be modulated by field effect. We have created a new perovskite dielectric oxide BaHf0.6Ti0.4O3 which exhibits both a high-k dielectric constant and a high dielectric strength (low leakage current and high breakdown field). Recently, polycrystalline BaHf0.6Ti0.4O3 has been successfully integrated as a superb gate oxide for GaN systems.
When a lattice matched ferroelectric PbZr0.7Ti0.3O3 is used as a gate oxide, ferroelectric FET can be realized. The structurally perfect interface at PbZr0.7Ti0.3O3/BaSnO3 can work as a model system to study the switching properties of ferroelectric/semiconductor structure. We will discuss the implications of the ferroelectric and semiconducting material parameters on the switching performance.
Lastly, using SrSnO3 with 4.6 eV bandgap, we demonstrated DUV-transparent FETs by integrating with the ultrawide bandgap LaScO3 as the gate oxide. The resultant device shows a high field effect mobility, a large on/off ratio, and high optical transmittance larger than 75% at 300 nm.
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Presenters
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Kookrin Char
- Seoul Natl Univ