RESUMEN
We report on a novel semiconductor reliability technique that incorporates an electrically detected magnetic resonance (EDMR) spectrometer within a conventional semiconductor wafer probing station. EDMR is an ultrasensitive electron paramagnetic resonance technique with the capability to provide detailed physical and chemical information about reliability limiting defects in semiconductor devices. EDMR measurements have generally required a complex apparatus, not typically found in solid-state electronics laboratories. The union of a semiconductor probing station with EDMR allows powerful analytical measurements to be performed within individual devices at the wafer level. Our novel approach replaces the standard magnetic resonance microwave cavity or resonator with a small non- resonant near field microwave probe. Using this new approach we have demonstrated bipolar amplification effect and spin dependent charge pumping in various SiC based MOSFET structures. Although our studies have been limited to SiC based devices, the approach will be widely applicable to other types of MOSFETs, bipolar junction transistors, and various memory devices. The replacement of the resonance cavity with the very small non- resonant microwave probe greatly simplifies the EDMR detection scheme and allows for the incorporation of this powerful tool with a wafer probing station. We believe this scheme offers great promise for widespread utilization of EDMR in semiconductor reliability laboratories.
RESUMEN
Rapid-scan electron paramagnetic resonance (RSEPR) results in a significant improvement in signal-to-noise over magnetic field modulated continuous wave EPR (CWEPR). However, the RSEPR raw absorption spectra can make the real-time comparison of CWEPR spectra difficult, especially in systems where the total number of paramagnetic spins is low. In this paper, we illustrate a method of applying pseudomodulation within RSEPR data collection software in real-time. Pseudomodulation is generally carried out in post-processing to increase signal-to-noise and simulate the effects of modulation on the spectra observed in traditional magnetic field modulated CWEPR. By applying the pseudomodulation method on a discrete computational basis, the technique can be utilized in parallel with data collection due to the significantly reduced computational power of the discretized pseudomodulation calculation. This allows for the live alteration of modulation parameters, such as the modulation amplitude and modulation harmonic. This real-time simulation allows for the comparison of the accumulated non-adiabatic rapid-sweep EPR spectra with the known CWEPR spectra available in the literature and has the ability to view smaller and less sensitive resonance features for various harmonics during high-frequency experiments while retaining all signal-to-noise improvements.
RESUMEN
We have significantly refined an adaptive signal averaging approach developed primarily for continuous wave electron paramagnetic resonance and electrically detected magnetic resonance measurements. This refinement overcomes several limitations and greatly simplifies the earlier approach. The new technique provides a large improvement in tracking and numerical stability and also features fewer adjustable parameters making this approach more user intuitive.
RESUMEN
We have developed a sensitive electron nuclear double resonance spectrometer in which the detection takes place through electrically detected magnetic resonance. We demonstrate that the spectrometer can provide reasonably high signal to noise spectra of 14N interactions with deep level centers in a fully processed bipolar junction transistor at room temperature.
RESUMEN
We report on a novel electron paramagnetic resonance (EPR) technique that merges electrically detected magnetic resonance (EDMR) with a conventional semiconductor wafer probing station. This union, which we refer to as wafer-level EDMR (WL-EDMR), allows EDMR measurements to be performed on an unaltered, fully processed semiconductor wafer. Our measurements replace the conventional EPR microwave cavity or resonator with a very small non-resonant near-field microwave probe. Bipolar amplification effect, spin dependent charge pumping, and spatially resolved EDMR are demonstrated on various planar 4H-silicon carbide metal-oxide-semiconductor field-effect transistor (4H-SiC MOSFET) structures. 4H-SiC is a wide bandgap semiconductor and the leading polytype for high-temperature and high-power MOSFET applications. These measurements are made via both "rapid scan" frequency-swept EDMR and "slow scan" frequency swept EDMR. The elimination of the resonance cavity and incorporation with a wafer probing station greatly simplifies the EDMR detection scheme and offers promise for widespread EDMR adoption in semiconductor reliability laboratories.
RESUMEN
Magnetometers are essential for scientific investigation of planetary bodies and are therefore ubiquitous on missions in space. Fluxgate and optically pumped atomic gas based magnetometers are typically flown because of their proven performance, reliability, and ability to adhere to the strict requirements associated with space missions. However, their complexity, size, and cost prevent their applicability in smaller missions involving cubesats. Conventional solid-state based magnetometers pose a viable solution, though many are prone to radiation damage and plagued with temperature instabilities. In this work, we report on the development of a new self-calibrating, solid-state based magnetometer which measures magnetic field induced changes in current within a SiC pn junction caused by the interaction of external magnetic fields with the atomic scale defects intrinsic to the semiconductor. Unlike heritage designs, the magnetometer does not require inductive sensing elements, high frequency radio, and/or optical circuitry and can be made significantly more compact and lightweight, thus enabling missions leveraging swarms of cubesats capable of science returns not possible with a single large-scale satellite. Additionally, the robustness of the SiC semiconductor allows for operation in extreme conditions such as the hot Venusian surface and the high radiation environment of the Jovian system.