(p⁺)Nanocrystalline/(n⁻)crystalline/(n⁺)nanocrystalline Si fast recovery diode with (p⁺)nanocrystalline SiC inserted in cathode junction

Surge suppressed by (p⁺)nanocrystalline SiC islands buried in cathode junction of operating (p⁺)nanocrystalline/(n⁻)crystalline/(n⁺)nanocrystalline Si fast recovery diode was studied in this paper. The proposed diode was prepared by plasma enhanced chemical vapor deposition (PECVD) technique. Firstly, heavily boron doped Si film was prepared with PECVD on one end of the lightly doped n⁻-type cubic Si (c-Si) substrate to form an anode. Hereafter, heavily boron doped SiC layer was deposited in the lithography mask etched pits in another side of c-Si, heavily phosphorus doped Si film was subsequently grown on the end inserted SiC to form a cathode. For a comparison, a traditional p⁺-n⁻-n⁺ type device without SiC was fabricated by the PECVD growing heavily boron and heavily phosphorus doped films on two sides of the c-Si respectively. Nanocrystallization was demonstrated by X-ray diffraction and high resolution transmission electron microscopy in the fabricated films. Capacitance vs. voltage relation, current vs. voltage feature and reverse recovery waveform were measured to reveal the performance of the studied components. The important roles of (p⁺)nanocrystalline SiC in the static and dynamic conduction processes in operating device were probed, which indicates that the reverse recovery behaviors were improved.