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Significant progress has been achieved with silicon carbide (SiC) high power electronics and quantum technologies, both drawing upon the unique properties of this material. In this Perspective, we briefly review some of the main defect characterization techniques that have enabled breakthroughs in these fields. We consider how key data have been collected, interpreted, and used to enhance the application of SiC. Although these fields largely rely on separate techniques, they have similar aims for the material quality and we identify ways in which the electronics and quantum technology fields can further interact for mutual benefit.

The steady-state, space-charge-limited piezoresistance (PZR) of defect-engineered, silicon-on-insulator device layers containing silicon divacancy defects changes sign as a function of applied bias. Above a punch-through voltage ($V_t$) corresponding to the onset of a space-charge-limited hole current, the longitudinal $\langle 110 \rangle$ PZR $\pi$-coefficient is $\pi \approx 65 \times 10^{-11}$~Pa$^{-1}$, similar to the value obtained in charge-neutral, p-type silicon. Below $V_t$, the mechanical stress dependence of the Shockley-Read-Hall (SRH) recombination parameters, specifically the divacancy trap energy $E_T$ which is estimated to vary by $\approx 30$~$\mu$V/MPa, yields $\pi \approx -25 \times 10^{-11}$~Pa$^{-1}$. The combination of space-charge-limited transport and defect engineering which significantly reduces SRH recombination lifetimes makes this work directly relevant to discussions of giant or anomalous PZR at small strains in nano-silicon whose characteristic dimension is larger than a few nanometers. In this limit the reduced electrostatic dimensionality lowers $V_t$ and amplifies space-charge-limited currents and efficient SRH recombination occurs via surface defects. The results reinforce the growing evidence that in steady state, electro-mechanically active defects can result in anomalous, but not giant, PZR., Comment: 9 pages, 8 figures

The SiC/SiO2 interface is a central component of many SiC electronic devices. Defects intrinsic to this interface can have a profound effect on their operation and reliability. It is therefore crucial to both understand the nature of these defects and develop characterization methods to enable optimized SiC-based devices. Here we make use of confocal microscopy to address single SiC/SiO2-related defects and show the technique to be a noncontact, nondestructive, spatially resolved and rapid means of assessing thequality of the SiC/SiO2 interface. This is achieved by a systematic investigation of the defect density of the SiC/SiO2 interface by varying the parameters of a nitric oxide passivation anneal after oxidation. Standard capacitance-based characterization techniques are used to benchmark optical emission rates and densities of the optically active SiC/SiO2-related defects. Further insight into the nature of these defects is provided by low-temperature optical measurements on single defects.

Color centers that emit light at telecommunication wavelengths are promising candidates for future quantum technologies. A pressing challenge for the broad use of these color centers is the typically low collection efficiency from bulk samples. Here, we demonstrate enhancements of the emission collection efficiency for Er3+ incorporated into 4H-SiC surface nano-pillars fabricated using a scalable top-down approach. Optimal Er ion implantation and annealing strategies are investigated in detail. The substitutional fraction of Er atoms in the SiC lattice is closely correlated with the peak photoluminescence intensity. This intensity is further enhanced via spatial wave-guiding once the surface is patterned with nano-pillars. These results have broad applicability for use with other color centers in SiC and also demonstrate a step toward a scalable protocol for fabricating photonic quantum devices with enhanced emission characteristics.

A giant, anomalous piezo-response of fully-depleted silicon-on-insulator (FD-SOI) devices under mechanical stress is demonstrated using impedance spectroscopy. This piezo-response strongly depends on the measurement frequency, $\omega$, and consists of both a piezoresistance (PZR) and piezocapacitance whose maximum values are $\pi_R = -1100 \times 10^{-11}$ Pa$^{-1}$ and $\pi_C = -900 \times 10^{-11}$ Pa$^{-1}$ respectively. These values should be compared with the usual bulk PZR in p-type silicon, $\pi_R= 70 \times 10^{-11}$ Pa$^{-1}$. The observations are well described using models of space charge limited electron and hole currents in the presence of fast electronic traps having stress-dependent capture ($\omega_c$) and emission rates. Under steady-state conditions (i.e. when $\omega \ll \omega_c$) where the impedance spectroscopy measurements yield results that are directly comparable with previously published reports of PZR in depleted, silicon nano-objects, the overall piezo-response is just the usual, bulk silicon PZR. Anomalous PZR is observed only under non-steady-state conditions when $\omega \approx \omega_c$, with a symmetry suggesting that the electro-mechanically active fast traps are native Pb$_0$ interface defects. The observations suggest new functionalities for FD-SOI, and shed light on the debate over the PZR of carrier depleted nano-silicon., Comment: 14 pages with 10 figures including appendices

Surfaces and interfaces can dominate charge carrier transport dynamics in electronic devices, impeding realization of a material's full potential. Here, we investigate transport in a two-terminal diamond device comprising a conductive channel defined by a hydrogen-terminated diamond surface, bridging two TiC contacts. The surface charge distribution was imaged by monitoring the photoluminescence of nitrogen vacancy centers incorporated below the active device layer. A strong charge accumulation near the TiC contact/H-terminated channel interface is observed and is discussed in terms of deviation from Ohmic behavior evident in the DC electrical measurements. Small voltage steps applied to the device result in current transients due to carrier trapping at the contact/diamond interface. This gives rise to dynamic negative capacitance at low AC frequencies and is discussed in detail.

Au-hyperdoped Si absorbs near-infrared (NIR) light and recent efforts have successfully produced Si-based NIR photodetectors based on this property but with low detection efficiencies. Here, we investigate the differences between the optical and photocurrent properties of Au-hyperdoped Si. Although defects introduced during fabrication of these materials may not exhibit significant optical absorption, we show that they can produce a measurable photocurrent under NIR illumination. Our results indicate that the optimal efficiency of impurity-hyperdoped Si materials is yet to be achieved and we discuss these opportunities in light of our results. This work thus represents a step forward in demonstrating the viability of using impurity-hyperdoped Si materials for NIR photodetection.

Hyperdoped Si formed by implantation followed by pulsed laser melting is a promising material for enhanced near-infrared photodetection. To realize the full potential of this material, it is crucial to understand the nature of defects arising from the fabrication process and how these may impact device operation. Here, we identify through deep level transient spectroscopy the presence of a range of defects in the substrate depletion layer that arise from interactions between high dose ion implantation and pulsed laser melting, and investigate their annealing behavior up to 650 °C. In particular, the detection of a vacancy complex E 1 ( 0.35 ) with densities as high as 10 14 cm − 3 indicates that optical transitions between this level and the valence band may compete with the Au donor center, and hence could potentially contribute to the photocurrent in hyperdoped photodiodes.

Defects introduced by low fluence arsenic, antimony, erbium, and bismuth ion implantation have been investigated as a function of annealing temperature using deep level transient spectroscopy (DLTS) and Laplace-DLTS. The defects produced by heavy ion implantation are stable up to higher temperatures than those introduced by electron irradiation and low mass ions. This result is attributed to the enhanced defect interactions that take place in the dense collision cascades created by heavy ion implantation. As a consequence, broadened DLTS features are apparent, especially after annealing. Using high energy resolution Laplace-DLTS, the well-known singly charged divacancy and vacancy-donor pair are accompanied by additional apparent defect signals. This shows that Laplace-DLTS is highly sensitive to the type of damage present, and extreme care must be exercised for reliable Arrhenius analysis.