Schottky Diode Isolation Contact Structure for Higher Breakdown Voltage

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Solution Overview

Problem

Existing Schottky barrier diodes have relatively low breakdown voltage, limiting their operational voltage and suitability for various applications.

Innovation Solution

Incorporating contact features into the isolation region between the anode and cathode of the Schottky diode, such as shallow trench isolation, to enlarge the depletion region and increase breakdown voltage, using a resist protective oxide film and multi-layer dielectric stacks during the fabrication process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a Schottky diode uses a simple metal-semiconductor contact structure, then the device complexity is low and manufacturing is easy, but the breakdown voltage is limited

Engineering Contradiction:

Improvebreakdown voltageVSAvoiddevice structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The isolation region is segmented into multiple regions with different doping types and concentrations. Specifically, the isolation region includes a first region with a first doping type and a second region with a second doping type opposite to the first, creating distinct functional zones that collectively enhance the breakdown voltage while maintaining structural organization

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the isolation structure are assigned different local properties through varying doping types and concentrations. The first isolation region has different electrical characteristics than the second isolation region, allowing each region to contribute differently to the overall breakdown voltage enhancement

Inventive Principle:

Principle #3Local quality

2Reliability

If the Schottky diode structure is modified to increase breakdown voltage, then the operational voltage range expands, but the manufacturing process becomes more complex

Engineering Contradiction:

Improvebreakdown voltageVSAvoidfabrication process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The isolation regions are formed preliminarily during the device fabrication process before the Schottky contact is finalized. By pre-establishing the doped isolation regions with appropriate doping profiles, the structure is prepared in advance to support higher breakdown voltages without requiring additional complex processing steps later

Inventive Principle:

Principle #10Preliminary action

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

The method enhances the breakdown voltage of Schottky barrier diodes, enabling them to operate at higher voltages and be suitable for a wider range of applications.

Implementation Method 1

a metal contact that extends through the patterned RPO layer and extends into the isolation feature

Methodology Applied

Scientific EffectSchottky barrier:

Implementation Method 2

enlarge the depletion region and increase breakdown voltage

Methodology Applied

Scientific EffectDepletion region: Electric Field

Data Source

PatentUS20240258439A1Schottky diode and method of fabrication thereof

Publication Date: 2024.08.01 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method of forming a semiconductor device includes providing a first isolation feature in a substrate, where the first isolation feature defines and isolates a cathode region of a Schottky barrier diode (SBD) from an anode region of the SBD. In some embodiments, the method further includes forming a patterned resist protective oxide (RPO) layer over the first isolation feature. Thereafter, the method further includes forming a first metal contact that extends through the patterned RPO layer and extends into the first isolation feature.