Integrated Circuit Schottky Diode Contact Window Integration

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Solution Overview

Problem

The integration of Schottky diodes with integrated circuits is hindered by the need for extra layout designs and assembly, increasing costs and compromising device integrity, as existing methods cannot form Schottky diodes on the same chip as interconnection lines, and require low-resistance metals for efficient operation.

Innovation Solution

An integrated circuit structure is developed where a substrate with heavily and lightly doped regions is used, with a contact window and Schottky contact metal layer formed of different materials, allowing simultaneous integration of the Schottky diode with the contact window on the same chip, using materials like tungsten for the contact window and low-resistance metals like aluminum for the Schottky contact metal, along with barrier layers and spacers to enhance adhesion and electrical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If tungsten metal is used to form the contact window during the back process, then the trench filling ability is improved, but the Schottky diode cannot be integrated with the contact window on the same chip

Engineering Contradiction:

Improvetrench filling abilityVSAvoidintegration complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the metal layer formation process into two distinct parts: a contact window formed by tungsten metal for superior trench filling, and a Schottky contact metal layer formed by a different material (such as aluminum, copper, or platinum) for rectification functionality. This segmentation allows each metal layer to be optimized for its specific function while being integrated on the same chip.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by using different materials for different regions of the metal layer. The contact window region uses tungsten metal for its excellent trench filling properties, while the Schottky contact region uses a different metal material optimized for rectification. This localized material selection resolves the contradiction between trench filling ability and integration capability.

Inventive Principle:

Principle #3Local quality

2Reliability

If the Schottky diode is formed on another chip, then the rectification function is achieved, but extra layout designs and assembly are required

Engineering Contradiction:

Improverectification functionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the Schottky diode formation process with the integrated circuit manufacturing process by forming both the contact window and the Schottky contact metal layer on the same chip during the same manufacturing sequence. This consolidation eliminates the need for separate chip fabrication and assembly operations, reducing manufacturing costs while maintaining rectification functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a multi-functional metal layer structure that simultaneously serves as both a contact window (for electrical connection) and a Schottky diode (for rectification). This universal structure performs multiple functions on a single chip, eliminating the need for separate components and assembly processes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If a low-resistance metal is used for the Schottky contact metal layer, then the electrical property is improved, but the material selection is limited

Engineering Contradiction:

Improveelectrical propertyVSAvoidmaterial selection flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent optimizes the electrical properties of the Schottky diode by carefully selecting metal materials with appropriate resistance characteristics for the Schottky contact metal layer. By changing material parameters (such as choosing aluminum, copper, or platinum with their respective low-resistance properties), the patent achieves improved electrical performance while maintaining versatility in material selection.

Inventive Principle:

Principle #35Parameter changes

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 approach reduces design and assembly costs, improves device integrity, and enhances electrical properties by integrating the Schottky diode with the contact window on the same chip, utilizing metals with superior trench filling ability and low-resistance metals for improved performance.

Implementation Method 1

since the Schottky diode achieves rectification by utilizing the work function difference between the lightly doped semiconductor layer and the metal layer thereon

Methodology Applied

Scientific EffectWork function difference:

Data Source

PatentUS7701031B2Integrated circuit structure and manufacturing method thereof

Publication Date: 2010.04.20 UNITED MICROELECTRONICS CORP

AI summary

An integrated circuit structure is described, and includes a substrate, a contact window, and a Schottky contact metal layer. A heavily doped region and a lightly doped region are formed in the substrate. The contact window is disposed above the heavily doped region, and the Schottky contact metal layer is disposed above the lightly doped region. The Schottky contact metal layer and the substrate form a Schottky diode. The material of the contact window is different from that of the Schottky contact metal layer.