Emission of Trapped Electrons from the 4H-SiC/SiO2-Interface via Photon-Irradiance at Cryogenic Temperatures

Magdalena Weger; Michel Bockstedte; Gregor Pobegen

doi:10.4028/p-F0SOLi

Paper Titles

Early Detection of Bar-Shaped 1SSF before Expansion by PL Imaging
p.33

Analysis of Forward Bias Degradation Reduction in 4H-SiC PiN Diodes on Bonded Substrates
p.39

Investigation of Dislocation Behaviors in 4H-SiC Substrate during Post-Growth Thermal Treatment
p.45

The Role of Defects on SiC Device Performance and Ways to Mitigate them
p.51

Emission of Trapped Electrons from the 4H-SiC/SiO₂-Interface via Photon-Irradiance at Cryogenic Temperatures
p.61

SiC MOSFET Gate Oxide Quality Improvement Method in Furnace Thermal Oxidation with Lower Pressure Control
p.67

Investigating Dislocation Arrays Induced by Seed Scratches during PVT 4H-SiC Crystal Growth Using Synchrotron X-Ray Topography
p.71

Crystal Originated Defect Monitoring and Reduction in Production Grade SmartSiC™ Engineered Substrates
p.81

Analysis of Lattice Damage in 4H-SiC Epiwafers Implanted with High Energy Al Ions at Elevated Temperatures
p.87

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Emission of Trapped Electrons from the 4H-SiC/SiO₂-Interface via Photon-Irradiance at Cryogenic Temperatures

Abstract:

For a reliable MOSFET performance it is crucial to identify and reduce device performance limiting 4H-SiC/SiO₂ interface defects. Previous studies have focused on the quantification of the interface states density, however, the atomic defect structure is still to be investigated. Here, we introduce a new approach based on opto-electrical measurements, which allow to determine the energetic position of interface defects. The measurement routine is performed at cryogenic temperatures to suppress the thermal emission of electrons, which were trapped at interface states during the cooldown processed (from 300 K to 15 K) while a positive gate voltage of 50 V was applied. At 15 K the photon-assisted emission of trapped electrons is measured in dependence on the photon’s energy (1.8 eV-3 eV). The reduction of the threshold voltage is taken as an indicator for the amount of released charges after each photon irradiation. We found an enhanced emission efficiency at certain photon energies, especially at 2.8 eV. Near-interface-traps (NITs), reported by Afanasev et al. are located close to the measuredtrap level with E_NIT = E_{C, SiO2}−2.77(5) eV. Recently, El-Sayed et al. suggested wide-angle O-Si-Obonds as defect configuration, that act as electron traps and have a similar energy as the measure traplevel.