Improved interface and electrical properties of atomic layer deposited Al 2 O 3 /4H-SiC

Influence of annealing environment on the ALD-Al2O3/4H-SiC interface studied through XPS

“…Following these surface cleaning procedures, all the samples were additionally dipped in weak RCA 1 clean, where the solution was diluted to 1/3rd (100 ml NH 4 : 2000 ml DI H 2 O: 400 ml H 2 O 2 solution at 60 °C), for 10 min and later rinsed for 180 s in DI water. Afterwards, native oxide was removed by dipping all the samples in HF (5%) for 30 s and rinsing in DI water for 300 s. The surface cleaning process was previously optimized by comparing it with standard surface cleaning procedures [27]. Just after these surface treatments, the samples were placed in BENEQ TFS 200 ALD system to deposit Al 2 O 3 .…”

Structural and Insulating Behaviour of High-Permittivity Binary Oxide Thin Films for Silicon Carbide and Gallium Nitride Electronic Devices

“…A variety of SiC surface-cleaning treatments have been proposed, based either on wet chemical solutions [44][45][46] or plasma [47][48][49]. The most used chemical solutions for SiC cleaning are combinations of diluted sulfuric acid, hydrogen peroxide, isopropanol, diluted hydrofluoric acid.…”

“…The most used chemical solutions for SiC cleaning are combinations of diluted sulfuric acid, hydrogen peroxide, isopropanol, diluted hydrofluoric acid. Suvanam et al [46] demonstrated that RCA treatment [45], followed by HF diluted solution and finally isopropanol, was a good route to improve the interfacial electrical characteristics of Al 2 O 3 films on SiC, obtaining a density of interface states D it = 1.5 × 10 11 eV −1 cm −2 at E C − E t = 0.2 eV below the 4H-SiC conduction band edge, which was about two orders of magnitude lower than the values found with thermal SiO 2 . In regard to plasma treatment before high-κ deposition, H 2 plasma has been also evaluated in some works [47][48][49], since it represents an efficient route for the passivation of dangling bonds on SiC surfaces.…”

“…In particular, Yoshioka et al [47] demonstrated optimization of the interface of aluminium oxide and SiC without a SiO2 interlayer, resulting in a low Dit for the metal oxide semiconductor (MOS) capacitor of 1.7 × 10 12 cm −2 eV −1 at EC − Et = 0.2 eV and a peak field-effect mobility of 57 cm 2 V −1 s −1 that was quite constant with the variation of the gate bias. Other works have tried to figure out the right combination of semiconductor surface pre-treatments and postdeposition annealing in order to improve the electrical properties of Al2O3/SiC interfaces [41,46]. However, a key aspect is the channel mobility at the operative gate bias.…”

Imaging ultra-weak UV light below 100 pW cm−2 using a 4H–SiC photodetector with an Al2O3 interfacial layer

“…23–25 Especially, it has been proved that Al 2 O 3 deposited by atomic layer deposition (ALD) can efficiently passivate the surface defects of 4H–SiC. 26,27 So far, the introduction of ALD produced Al 2 O 3 (ALD-Al 2 O 3 ) into 4H–SiC based photodetectors for performance improvement has not been reported.…”