We report on a nanomechanical engineering method to monitor matter growth in real time via e-beam electromechanical coupling. This method relies on the exceptional mass sensing capabilities of nanomechanical resonators. Focused electron beam-induced deposition (FEBID) is employed to selectively grow platinum particles at the free end of singly clamped nanotube cantilevers. The electron beam has two functions: it allows both to grow material on the nanotube and to track in real time the deposited mass by probing the noise-driven mechanical resonance of the nanotube. On the one hand, this detection method is highly effective as it can resolve mass deposition with a resolution in the zeptogram range; on the other hand, this method is simple to use and readily available to a wide range of potential users because it can be operated in existing commercial FEBID systems without making any modification. The presented method allows one to engineer hybrid nanomechanical resonators with precisely tailored functionalities. It also appears as a new tool for studying the growth dynamics of ultrathin nanostructures, opening new opportunities for investigating so far out-of-reach physics of FEBID and related methods.

No abstract

SiC based metal-oxide-semiconductor field-effect transistors (MOSFETs) have gained a significant importance in power electronics applications. However, electrically active defects at the SiC/SiO 2 interface degrade the ideal behavior of the devices. The relevant microscopic defects can be identified by electron paramagnetic resonance (EPR) or electrically detected magnetic resonance (EDMR). This helps to decide which changes to the fabrication process will likely lead to further increases of device performance and reliability. EDMR measurements have shown very similar dominant hyperfine (HF) spectra in differently processed MOSFETs although some discrepancies were observed in the measured g-factors. Here, the HF spectra measured of different SiC MOSFETs are compared and it is argued that the same dominant defect is present in all devices. A comparison of the data with simulated spectra of the C dangling bond (P bC ) center and the silicon vacancy (V Si ) demonstrates that the P bC center is a more suitable candidate to explain the observed HF spectra. a) gernot.gruber@alumni.tugraz.at 1 arXiv:1709.08664v1 [cond-mat.mtrl-sci]

Anneals in nitrogen (N) containing atmosphere have been proven as efficient means of improving the channel mobility of SiC MOSFETs. It has been demonstrated that simultaneously the density of interface traps is reduced. However, this process is not yet fully understood. In this study we show a comparison of MOSFETs annealed in different atmospheres and compare their electrically detected magnetic resonance (EDMR) spectra with electrical parameters. We find hints for the N incorporation not only passivating but also creating or transforming defects.

Electrically detected magnetic resonance (EDMR) is a powerful technique for the observation and categorization of paramagnetic defects within semiconductors. The interpretation of the recorded EDMR spectra has long proved to be challenging. Here, defect spectra are identified by comparing EDMR measurements with extensive ab initio calculations. The defect identification is based upon the defect symmetry and the form of the hyperfine (HF) structure. A full description is given of how an accurate spectrum can be generated from the theoretical data by considering some thousand individual HF contributions out of some billion possibilities. This approach is illustrated with a defect observed in nitrogen implanted silicon carbide (SiC). Nitrogen implantation is a high energy process that gives rise to a high defect concentration. The majority of these defects are removed during the dopant activation anneal, shifting the interstitial nitrogen to the desired substitutional lattice sites, where they act as shallow donors. EDMR shows that a deep-level defect persists after the dopant activation anneal. This defect is characterized as having a gc∥B=2.0054(4) and gc⊥B=2.0006(4), with pronounced hyperfine shoulder peaks with a 13 G peak to peak separation. The nitrogen at a carbon site next to a silicon vacancy (NCVSi) center is identified as the persistent deep-level defect responsible for the observed EDMR signal and the associated dopant deactivation.