Field of Expertise: Advanced Material Science

Investigation of performance limiting point defects in SiC MOSFETs using electrically detected magnetic resonance
Gernot Gruber
15:00 - 17:00 Thursday 23 October 2014 Rechbauerstrasse 12, HSII

Defects at semiconductor-oxide interfaces in the channel of a transistor can act as trapping or scattering centers thereby limiting the carrier lifetime, degrading the carrier mobility, shifting the threshold voltage and causing parasitic device leakage currents. For certain high power applications, wide band gap materials such as Silicon Carbide (SiC) and Gallium Nitride (GaN) are of particular interest due to their superior intrinsic material properties (i.e. high breakdown voltage, high thermal conductivity, better switching performance…). Devices based on wide band gap semiconductor materials exhibit considerably higher defect densities than devices based on silicon technologies. The key for developing competitive and reliable wide band gap devices is to minimize the number of atomic scale defects by optimizing the processing parameters.
Electrically Detected Magnetic Resonance (EDMR) can be used to identify the microscopic structure of defects. EDMR is an experimental technique where the change of a current in a fully processed semiconductor device is used as a means to obtain the electron spin resonance (ESR) spectrum of electrically active defects in the device. ESR is the measurement of transitions between the Zeeman levels of the unpaired electrons in a magnetic field. The transitions are induced by a microwave field. Resonance is obtained when the microwave photons match the energy difference between the Zeeman levels which can be adjusted by sweeping the magnetic field. With this method the atomic structure of electrically active defects in a device can be measured. We present EDMR studies on defects at the SiC/SiO2 interface.