Spin dependent charge pumping: A new tool for MOS interface characterization

We have developed a new technique, spin dependent charge (SDCP) pumping which combines the unrivaled analytical power of EPR to identify the atomic scale nature of point defects with charge pumping, a widely used electrical characterization technique used to study interface/near interface defects in MOSFETs. We demonstrate SDCP to be a very powerful tool with potential to be of widespread use to the MOSFET characterization community. We study 4H SiC and Si based MOSFETs that have SiO₂ gate dielectrics with a new electrically detected magnetic resonance technique (EDMR). Our SDCP results demonstrate a tremendous improvement in sensitivity over the other EDMR techniques sensitive to interface near interface traps, spin dependent recombination (SDR). Additionally SDCP has the ability to access defects distributed over a wider energy range of the semiconductor bandgap than SDR. Charge pumping is a powerful electronic characterization technique which provides information about the electronic properties interface / near interface traps in MOSFETs. [1-3] However, charge pumping cannot provide information about the atomic scale structure of the interface trapping defects. Conventional electron paramagnetic resonance (EPR) has unrivaled analytical power to identify atomic scale structure of defect centers but cannot not provide a direct connection between defect structure and electronic properties. [4] Combining EPR and charge pumping we develop a tool, spin dependent charge pumping (SDCP), which can directly link electronic properties of defect centers and information about defect structure in a very direct way. SDR has been useful in the study of fully processed MOSFETs. [5-9] SDCP circumvents some of the limitations of SDR, and also offers a very large increase in sensitivity over conventional SDR.