High-Voltage 4H-SiC-Based Avalanche Diodes with a Negative Bevel

• Published in: Semiconductors (Woodbury, N.Y.) Vol. 55; no. 4; pp. 405 - 409
• Main Authors: Ivanov, P. A., Lebedeva, N. M., Il’inskaya, N. D., Samsonova, T. P., Kon’kov, O. I.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.04.2021; Springer; Springer Nature B.V
• Subjects: Avalanche diodes; Avalanches; Bevels; Breakdown; Circuits; Current pulses; Current voltage characteristics; Diodes; Electron avalanche; Energy dissipation; High voltages; Inclination angle; Magnetic Materials; Magnetism; Mathematical analysis; Mesas; Photoresists; Physics; Physics and Astronomy; Reactive ion etching; Silicon carbide; Voltage drop; Walls; silicon carbide; high-voltage avalanche diode; negative bevel
• ISSN: 1063-7826; 1090-6479
• DOI: 10.1134/S1063782621040059

High-voltage avalanche p + – p – n 0 – n + diodes based on 4 H –SiC are fabricated. The diodes are made in the form of mesa structures with flat side walls forming a negative bevel. The mesa structures are formed by the dry reactive ion etching of 4 H -SiC through a wedge-shaped photoresist mask. The mesas have an area of 1 mm 2 , a height of 3.6 μm (slightly exceeding the bedding depth of 3 μm of the p – n 0 junction), and the angle of inclination of the side walls is ~5° from the plane of the p – n 0 junction. The I – V characteristics of the manufactured diodes are measured. At a current of 10 A, the differential resistance of the diodes and the voltage drop in the forward direction are 0.35 Ω and 6.5 V, respectively. In the reverse direction, the diodes exhibit an abrupt breakdown at voltages from 1420 to 1500 V. Using TCAD simulation, the reverse I – V characteristic of an idealized one-dimensional diode with the same parameters of the structure as in real diodes is calculated. The calculated voltage of a one-dimensional avalanche breakdown diode (1450 V) falls within the measured value range; i.e., the efficiency of the negative bevel as a security circuit is close to 100%. The pulsed reverse I – V characteristics of diodes in the powerful-avalanche breakdown mode are measured: the differential resistance is ~3 Ω, which indicates that the avalanche breakdown is uniform in area. The diodes withstand without destruction avalanche-current pulses with an amplitude of at least 10 A (current density of 10 3 A/cm 2 ) and a duration of 1.2 μs (dissipated energy of 9 mJ).