Fabrication of sic ultrafast recovery diode and its technology

Abstract

The invention discloses a base region gradient P<+>-N-N<+> type SiC ultrafast recovery diode manufactured on a 4H type single crystal silicon carbide epitaxial layer and a process. An anode / (P<+>)4H-nc-SiC / (N) slowly changes into a 6H-nc-SiC / (N)4H-c-SiC / (N<+>)4H-c-SiC / cathode. The base region gradient P<+>-N-N<+> type SiC ultrafast recovery diode comprises an N<+> type 4H-c-SiC substrate, an N type 4H-c-SiC epitaxial layer, an N type 6H-nc-SiC gradually-doped and grain-gradient multilayer film and a P<+> type 4H-c-SiC single layer film, wherein the outer sides of the N<+> type 4H-c-SiC substrate and the P<+> type 4H-c-SiC single layer film are in ohm connection with an anode NiAu and an anode TiAu respectively. The device structure is made by using a PECVD (Plasma Enhanced Chemical Vapor Deposition) technology. The process has the advantages of shortening the reverse recovery time, inhibiting surge current and lowering the process temperature.

Description

technical field [0001] The invention belongs to the field of power semiconductor devices, and specifically refers to a base gradient P prepared on a 4H type single crystal silicon carbide epitaxial layer. + -N-N + Type SiC ultrafast recovery diode and process. Background technique [0002] Fast Recovery Diode (FRD for short) used in power conversion or control and communication fields is usually used in conjunction with three-terminal power switching devices such as insulated gate-gated bipolar transistors (IGBT) or used alone to conduct Reactive current, shortening the charging time of capacitors, and suppressing electromagnetic interference caused by diffuse inductance, has extensive research and development and application value. [0003] Already have P + -N - -N + Commercial FRDs of crystalline silicon carbide (3c-SiC, 4H-SiC, 6H-SiC and other structural types) and crystalline silicon (c-SiC) materials are generally manufactured by epitaxy, diffusion, ion implantati...

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Problems solved by technology

In the past, the inventor designed a diode with a slow-changing anode and cathode and a constant base, and applied for the patent of "nano silicon carbide / crystalline silicon carbide double slow-changing junction fast recovery diode and its preparation method" (patent application number 201210329426.2), but 6H-nc-SiC structure not used

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