Materials Science Forum Vol. 1159

Abstract: Currently, silicon carbide (SiC) is widely recognized as a wide bandgap semiconductor, with expanding applications in harsh environments, such as high temperature and radiation exposure. In this study, we fabricated a planar structure 4H-SiC gate-all-around junction field-effect transistor (JFET), wherein the channel region is formed through ion implantation at varying doses. We successfully produced both normally-on and normally-off JFETs. Moreover, we constructed a JFET commonsource amplifier. The amplifiers achieved a maximum gain of -226.7 (47.1 dB) at a supply voltage of V_DD = 30 V.

Abstract: In this paper, we investigate the electrical and structural characteristics of Al₂O₃-based high-k gate dielectrics, which were integrated into a gate-first, high-temperature manufacturing process having comparable thermal budget as needed in 4H-SiC metal-oxide-semiconductor field-effect transistor (MOSFET) production. MOS capacitors were chosen as test devices to examine the electrical performance in terms of current-voltage (I-V) and capacitance-voltage (C-V) behavior. Remarkably, even after processing temperatures of up to 1,000 °C for ohmic contact formation, the Al₂O₃ layers revealed highly uniform breakdown characteristics, low C-V hysteresis and a flat-band voltage (V_FB) that closely aligns with the theoretical value. Time-dependent dielectric breakdown (TDDB) measurements of the Al₂O₃ MOS capacitors, however, showed a clear reliability disadvantage concerning the intrinsic dielectric lifetime when comparing with the SiO₂ counterpart from commercial SiC production. Finally, to better understand the electrical behavior, transmission electron microscopy (TEM) analysis was conducted, pointing out that high-temperature processing causes the Al₂O₃ films to transition from an amorphous state to an ordered, polycrystalline structure.

Abstract: This report describes the application of titanium nitride (TiN) with a silicon nitride (SiN) intervening layer as a Schottky electrode in a Schottky barrier diode (SBD) made of 4H-silicon carbide (SiC). This reduced the Schottky barrier height (Φ_b) to 0.74eV at room temperature, and it was confirmed that the reduction in Φ_b was due not only to the application of TiN but also to the intervening layer containing SiN at the SiC/TiN interface. Furthermore, TiN with SiN was applied to a device as a Schottky electrode, and the electric field reduction effect was verified by changing the high energy implantation and JBS width. As a result, the forward voltage (V_f) was found to be reduced by a maximum of 0.23 V while suppressing leakage current. The reason for describing the interlayer as “intervening layer containing SiN” is that there may be other substances besides SiN.

Abstract: Silicon Carbide is an exceptionally hard and challenging to process semiconductor material. Effective device singulation retaining 100% die yield is hard to achieve with conventional saw dicing. Chips, microcracks and machining abrasions lead to reduced die strength and increased scrap. With rapid advancements in SiC device processing, resolving many fabrication issues, dicing yield losses are becoming an area of industrial concern. Plasma dicing has a proven track record in silicon and presents a potential solution to low yields during SiC dicing. Smooth vertical sidewalls with no machining damage, with etch rates approaching 5 μm/min, position SiC plasma dicing as a viable alternative ready for industrial uptake. Plasma etch processes development using Ni and Cu etch masks, with full singulation have been demonstrated, resulting in improved die strength compared to saw diced samples.