Silicon Carbide Semiconductor Device with Nickel Silicide Ohmic Contact

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Solution Overview

Problem

Conventional silicon carbide semiconductor devices with JBS structures face challenges in enhancing surge current capability due to high contact resistance between p-type regions and ohmic electrodes, leading to trade-offs in IFSM and Vf characteristics.

Innovation Solution

The silicon carbide semiconductor device incorporates nickel silicide films in ohmic contact with p-type regions, forming low-resistance ohmic regions and non-operating regions in a striped pattern, connected by high-resistance regions, which reduces contact resistance and disperses surge current effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If p-type regions are used to form high-resistance regions, then reverse leak current is suppressed, but contact resistance with ohmic electrodes remains high

Engineering Contradiction:

Improvereverse leak current suppressionVSAvoidcontact resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The nickel silicide film serves as an intermediary layer between the p-type regions and the front surface electrode. Beneath the nickel silicide, n-type impurity regions are introduced to create low-resistance ohmic contacts. This intermediary structure allows the p-type regions to maintain their reverse leak suppression function while the n-type regions provide low-resistance electrical contact.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration improves IFSM characteristics while maintaining Vf characteristics, enhancing surge current capability and reducing heat generation, thereby increasing the reliability of silicon carbide semiconductor devices.

Implementation Method 1

nickel silicide films in ohmic contact with p-type regions, forming low-resistance ohmic regions

Methodology Applied

Scientific EffectOhmic contact: Conduction (electrical)

Implementation Method 2

disperses surge current effectively

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS11309438B2Silicon carbide semiconductor device and method of manufacturing silicon carbide semiconductor device

Publication Date: 2022.04.19 FUJI ELECTRIC CO LTD

AI summary

A semiconductor device having, in a plan view, a termination region surrounding an active region. The semiconductor device includes a semiconductor substrate containing silicon carbide, a first-conductivity-type region provided in the semiconductor substrate at its first main surface, a plurality of first second-conductivity-type regions selectively formed in the semiconductor substrate at its first main surface, a plurality of silicide films respectively in ohmic contact with the first second-conductivity-type regions, a first electrode that is in contact with the silicide films to form ohmic regions, with the first second-conductivity-type regions to form non-operating regions, and with the first-conductivity-type region to form Schottky regions, a second electrode provided at a second main surface of the semiconductor substrate, and a second second-conductivity-type region provided in the termination region. The ohmic regions, the non-operating regions and the Schottky regions are formed in the active region in a striped pattern. The second second-conductivity-type region connects the ohmic regions and the non-operating regions.