AlGaN Nitride Layer Structure for Threshold and Leakage Control

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Solution Overview

Problem

Semiconductor devices face challenges in achieving improved characteristics such as high carrier mobility, high threshold voltage, and stable operation while minimizing leak current and impurity intrusion during manufacturing.

Innovation Solution

The semiconductor device incorporates a specific structure with Al x1 Ga 1-x1 N and Al x2 Ga 1-x2 N semiconductor regions, a nitride region with varying thicknesses, and insulating members to control current flow and suppress impurity intrusion, featuring a gate electrode position between source and drain electrodes, and utilizing AlN and AlGaN layers to enhance mobility and threshold voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If AlN and AlGaN layers are used to enhance carrier mobility and threshold voltage, then device characteristics are improved, but manufacturing complexity increases due to precise thickness control requirements

Engineering Contradiction:
Improvedevice characteristicsVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by systematically varying the thickness of AlN and AlGaN layers, and the Al composition ratio, to optimize device characteristics. Specific thickness ranges are defined for different layers to achieve high carrier mobility and threshold voltage while maintaining manufacturability through controlled parameter variations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining multiple semiconductor layers with different compositions (AlN, AlGaN, GaN) in a heterostructure. This composite approach enables simultaneous achievement of high carrier mobility through band alignment and high threshold voltage through material composition control, resolving the contradiction between performance improvement and manufacturing complexity.

Inventive Principle:
Principle #40Composite materials

2Reliability

If nitride region thickness is increased to suppress impurity intrusion, then device stability improves, but on-resistance increases

Engineering Contradiction:
Improvedevice stabilityVSAvoidon-resistance
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating a nitride region with non-uniform thickness distribution. The thickness varies across different regions of the nitride layer, allowing suppression of impurity intrusion in critical areas while maintaining lower resistance paths in current-conducting regions. This spatial variation in thickness resolves the contradiction between stability and on-resistance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses parameter changes by defining specific thickness ranges for the nitride region (1 nm to 10 nm) and varying the Al composition ratio to optimize the balance between impurity suppression and resistance. By controlling these parameters within specific ranges, the patent achieves both device stability and acceptable on-resistance levels.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If Al composition ratio is increased to achieve high carrier concentration, then threshold voltage control improves, but crystallinity may deteriorate

Engineering Contradiction:
Improvethreshold voltage controlVSAvoidcrystallinity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by defining an optimal range for the Al composition ratio (0.3 to 0.7) that balances threshold voltage control and crystallinity. Within this range, the material achieves sufficient bandgap engineering for voltage control while maintaining crystal structure stability. The patent also specifies thickness parameters that work synergistically with composition to preserve crystallinity.

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 configuration enables high carrier mobility, stable operation, and reduced leak current, while allowing for increased Al composition in the nitride region, facilitating high carrier concentration and crystallinity, and achieving appropriate threshold voltage and low on-resistance.

Implementation Method 1

utilizing AlN and AlGaN layers to enhance mobility and threshold voltage

Methodology Applied
Scientific EffectCarrier mobility enhancement:

Implementation Method 2

a nitride region with varying thicknesses, and insulating members to control current flow and suppress impurity intrusion

Methodology Applied
Scientific EffectImpurity suppression:

Data Source

PatentEP4418329A1Semiconductor device and method for manufacturing the same
Publication Date: 2024.08.21 KK TOSHIBA
  • EP4418329A1 patent drawingFigure 1
  • EP4418329A1 patent drawingFigure 2
  • EP4418329A1 patent drawingFigure 3~4

AI summary

A semiconductor device includes a first electrode (51), a second electrode (52), a third electrode (53), a first semiconductor region (10), a second semiconductor region (20), a first nitride region (30), and a first insulating member (41). The first semiconductor region includes Alx1Ga1-x1N (0 ≤ x1 < 1). The second semiconductor region includes Alx2Ga1-x2N (0 < x2 < 1, x1 < x2). A first nitride portion thickness (t31) along a second direction of the first nitride portion is thicker than a second nitride portion thickness (t32) along the first direction of the part of the second nitride portion. A first semiconductor portion thickness (t21) along the second direction of the first semiconductor portion is thicker than the first nitride portion thickness.