Channelling can have a profound effect on both the defect formation and the distribution of implanted atoms in crystalline materials. This holds particularly for SiC, where channelling effects are well known for conventional dopant impurities. In contrast, channelling effects for protons in SiC are much less studied, despite H is known to be a promising element for defect engineering in power device applications as well as quantum technologies. In this study, the effects of ion channelling on the depth distribution of medium energy proton implants in epitaxial 4H-SiC were investigated. N-type 4H-SiC epilayers, grown on the (0001) plane, were implanted with 350 keV protons to low (5e9 cm−2) and medium (6e14 cm−2) doses, with beam alignment ranging from 0° to 7° off the [0001] orientation towards the [112‾0] direction. The samples were measured by a combination of deep level transient spectroscopy (DLTS) and dynamic secondary ion mass spectrometry (D-SIMS), to reveal the role of ion channelling on the generation of defects and the distribution of implanted H. The experimental profiles were also compared to Monte Carlo binary collision approximation (MC-BCA) simulations. These measurements show that channelling implantation of protons in high quality epitaxial 4H-SiC can be used for discrete profile shape adjustments and peak depth control by playing with the beam alignment conditions, thus representing a valuable means for high precision localized in-depth control of electrically active defects.

Atomic layer deposited (ALD) TiO<inf>2</inf> layers are implanted with N, O, and Ar ions to reduce the bandgap, thereby increasing its absorbance in the visible region. The implantation is accomplished with 40 keV nitrogen, 45 keV oxygen, and 110 keV argon ions in the fluence range 1 × 10¹⁵ to 5.6 × 10¹⁶ ions cm⁻². The energy of each incident ion is tuned using stopping and range of ions in matter (SRIM) to produce defects around the same projected range. The structural analysis of the as-deposited film is performed through X-ray diffraction (XRD), scanning electron microscopy (SEM), Rutherford backscattering (RBS), and time of flight elastic recoil detection analysis (ToF-ERDA). The implanted layers are characterized using diffuse reflectance spectroscopy (DRS) and Fourier transform infrared spectroscopy (FTIR) to study the optical and vibrational properties of the films. The results demonstrate that nitrogen implantation in TiO<inf>2</inf> reduces the reflectance from 43.52% to 26.31% and bandgap from 2.68 to 2.61 eV, making it a promising bandgap-engineered material for capping layers in solar cell applications. The refractive index of the 40 keV nitrogen ion implanted film at 1 × 10¹⁶ ions cm⁻² (N-16) increases from ≈2.8 to ≈2.95. OPAL2 solar cell simulations show that the N-16 implanted TiO<inf>2</inf> anti-reflective coatings (ARC) can enhance the absorbed photocurrent by 7.3%.

Junction termination design has become a crucial process in ultrahigh-voltage 4H-SiC device design since it enhances the reliability and ensures that the device can reach the designed breakdown voltage. In this work, we review the blocking performances, fabrication considerations and area efficiencies of several typical termination structures widely used for ultrahigh-voltage 4H-SiC devices, and aim to optimize the termination design of next generation devices, focusing on improved termination efficiency, simultaneous design of breakdown voltage and surface field without introducing extra fabrication complexity and costs. The relationship between area efficiency, surface electric field and breakdown voltage is first described, indicating that improving the uniformity of electric field at the SiC/oxide interface is essential to improve the area efficiency. A buried termination structure, where implanted zones are buried under a thin field buffer layer，is proposed to obtain a nearly rectangular field distribution at the SiC/oxide interface. The termination pattern is then directly scaled without any iterative design process to optimize the termination area, and the simulation results show that the field distribution can be mostly preserved. Optimization and limitations that are related to fabrication and design considerations are also addressed in the end.

Silicon carbide (SiC) is a key material for electronics operating in harsh environments due to its wide bandgap, high thermal conductivity, and radiation hardness. In this work, we present a SPICE model for a 4H-SiC BJT and TTL inverter exposed to gamma radiation. The devices were fabricated using a dedicated SiC bipolar process at KTH (Sweden) and tested at the 60Co Calliope (Italy) facility up to 800 krad (Si). Experimental data, including Gummel plots and inverter transfer characteristics, were used to calibrate and refine a VBIC-based SPICE model. The adjusted model accounts for both bulk and surface degradation mechanisms by extracting parameters of forward current gain (beta F), saturation current (IS), base resistance (RB), and forward transit time (TF). Results show a uniform degradation of BJTs, primarily manifested as reduced current gain and increased base resistance, while the inverter maintained functional operation up to 600 krad(Si). Extrapolation of the SPICE model predicts a failure threshold near 16 Mrad(Si), far exceeding the tolerance of conventional silicon circuits. By linking radiation-induced defects at the material and interface levels to circuit-level behavior, the proposed model enables realistic design and lifetime prediction of SiC integrated circuits for satellites, planetary missions, and other radiation-intensive applications.

The study focuses on analysing the high-level carrier lifetime (tau(HL)) in 4H silicon carbide (4H-SiC) PiN diodes under varying temperatures and proton implantation doses. The objective is to identify an empirical law applicable in technology computer-aided design (TCAD) modelling for SiC devices, describing the dependence of carrier lifetime on temperature to gain insights into how irradiation dose may influence the tau(HL). We electrically characterize diodes of different diameters subjected to different proton irradiation doses and examine the variations in current-voltage (I-V) and ideality factor (n) curves under various irradiation conditions. The effects of proton irradiation on the epitaxial layer are analysed through capacitance-voltage (C-V) measurements. We correlate the observed effects on I-V, n, and C-V curves to the hypothesis of formation of acceptor-type defects related to carbon vacancies, specifically the Z(1/2) defects generated during the irradiation process. The impact of irradiation on carrier lifetime is investigated by measuring tau(HL) using the open circuit voltage decay (OCVD) technique at different temperatures on diodes exposed to various H+ irradiation doses with constant ion energy. This investigation reveals the presence of a proportional relationship between 1/ tau(HL) and the dose of irradiated protons: the proportionality coefficient, referred to as the damage coefficient (K-T), exhibits an Arrhenius-type dependence on temperature. OCVD-measured lifetime on the various diodes demonstrates a power-law dependence of lifetime on temperature. The exponent of this dependence varies with the irradiation dose, notably showing an increase in temperature dependence at the highest H+ ion dose. This suggests a threshold-like dependence on H+ irradiation dose in the tau(HL) -temperature relationship.

The knowledge of capture properties of electrically active defects is of primary importance as it helps to understand which deep states are effective in controlling the excess free carriers’ lifetime. Combining DLTS capture experiments with thermal emission measurements enables an overall thermodynamic description of deep states, thus making it possible to characterize recombination centers in semiconductor-based devices. In the present study, junction DLTS capture rate measurements were employed to extract the true capture cross-sections (inversely proportional to the carrier lifetime) and capture energy barriers for the main lifetime limiting defects in 4H-SiC(silicon carbide). A peculiar forward bias dependence of the capture parameters was observed for the shallow boron (B) hole trap. Capture rate measurements on the deep boron (D-center) trap also evidenced the presence of two capture mechanisms, thus allowing discrimination of D<inf>1</inf> and D<inf>2</inf> deep states within the D-center DLTS peak. The results were combined with activation energies and apparent capture cross-sections to obtain the free energy (ΔG) of electronic activation for the analysed deep states.

A pn-heterojunction is fabricated by depositing an n-type β-Ga2O3 film by pulsed laser deposition (PLD) on c-cut Al2O3. P-type cuprous oxide films, Cu2O, are then deposited by PLD, as well as by radio frequency (RF) magnetron sputtering. It is concluded that hole injection is prohibited by a 3.26 eV valence band barrier, as measured by X-ray photo-electron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Heterojunction diode structures are prepared on the front side and electrical measurements demonstrate a rectification ration of 8 orders of magnitude and an ideality factor close to 2, indicating interface recombination-controlled forward current. The junction is also optically active and shows a very fast photo-response to 275 nm UV light. 

Lithium niobate (LiNbO₃ exhibits poor radiation resistance when conventionally implanted with Er at room temperature. To repair the structural disorder, high-temperature post-implantation anneals are typically required; however, such treatments can cause sample cracking and dopant redistribution, which are incompatible with device applications. The optimized approach is proposed by performing implants at elevated but acceptably low temperatures to in situ minimize the structural defects generated in the collision cascades, via so-called “dynamic defect annealing”. Thus, a gradual increase in Er optical activity is shown as a function of irradiation temperature in the range of 25–450 °C, in striking correlation with a decreasing trend for the residual disorder. The impact of moderate post-implantation anneals is also investigated by comparing the results of anneals of samples implanted at 25 °C and 450 °C. This comparison further confirms the higher optical activation of Er and lower residual structural disorder when the material is initially implanted at elevated temperatures. Based on these data, it is concluded that the use of dynamic defect annealing during the Er implantation of LiNbO₃ is a promising strategy for optimizing it as a quantum memory platform, resolving otherwise inevitable trade-offs.

Self-charging power systems (SCPSs) are envisioned as promising solutions for emerging electronics to mitigate the increasing global concern about battery waste. However, present SCPSs suffer from large form factors, unscalable fabrication, and material complexity. Herein, a type of highly stable, eco-friendly conductive inks based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) are developed for direct ink writing of multiple components in the SCPSs, including electrodes for miniaturized spacer-free triboelectric nanogenerators (TENGs) and microsupercapacitors (MSCs), and interconnects. The principle of “one ink, multiple functions” enables to almost fully print the entire SCPSs on the same paper substrate in a monolithic manner without post-integration. The monolithic fabrication significantly improves the upscaling capability for manufacturing and reduces the form factor of the entire SCPSs (a small footprint area of ≈2 cm × 3 cm and thickness of ≈1 mm). After pressing/releasing the TENGs for ≈79000 cycles, the 3-cell series-connected MSC array can be charged to 1.6 V while the 6-cell array to 3.0 V. On-paper SCPSs are promising to serve as lightweight, thin, sustainable, and low-cost power supplies.