Semiconductor Substrate Oxygen Profile for Stable Device Characteristics

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Solution Overview

Problem

The characteristics of semiconductor devices vary significantly due to variations in oxygen concentration within the semiconductor substrate, leading to inconsistent performance across devices.

Innovation Solution

A semiconductor device with a controlled oxygen concentration distribution is achieved by annealing the substrate at a temperature that exceeds the initial oxygen concentration, allowing oxygen to diffuse uniformly, and then grinding the substrate to adjust the thickness, thereby creating a high oxygen concentration peak followed by a gradual decrease, which stabilizes the oxygen concentration across the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If oxygen concentration in the semiconductor substrate is not controlled, then manufacturing process is simpler, but device characteristics vary significantly

Engineering Contradiction:
Improvedevice characteristics consistencyVSAvoidoxygen concentration control process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Oxygen is introduced into the semiconductor substrate before the main device fabrication process through pre-treatment steps such as plasma treatment or thermal diffusion. This preliminary oxygen incorporation ensures consistent oxygen concentration throughout the substrate, establishing a reliable foundation for subsequent processing and eliminating variability in device characteristics.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The oxygen concentration in the semiconductor substrate is controlled by adjusting processing parameters such as annealing temperature, oxygen partial pressure, and treatment duration. By systematically varying these parameters during manufacturing, the oxygen concentration can be precisely tuned to achieve consistent device performance across production batches.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If oxygen concentration is increased to improve device performance, then device characteristics improve, but oxygen diffusion control becomes more difficult

Engineering Contradiction:
Improvedevice performanceVSAvoidoxygen diffusion control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

Different oxygen concentrations are introduced into different regions of the semiconductor substrate according to specific device requirements. For example, higher oxygen concentrations are applied to regions requiring enhanced thermal stability or reduced defect density, while other regions maintain lower oxygen levels. This spatially differentiated approach optimizes device performance while maintaining controllable oxygen diffusion profiles.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Oxygen diffusion is maintained continuously or in multiple staged steps during the manufacturing process rather than as a single discrete operation. This continuous oxygen incorporation ensures uniform distribution and prevents localized oversaturation, making the diffusion process more controllable while achieving the desired oxygen concentration levels throughout the substrate.

Inventive Principle:
Principle #20Continuity of useful 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

This method effectively reduces variations in oxygen concentration and device characteristics, enhancing the reliability and consistency of semiconductor performance by managing the annealing temperature and process to achieve a predetermined oxygen distribution.

Implementation Method 1

annealing the substrate at a temperature that exceeds the initial oxygen concentration

Methodology Applied
Scientific EffectAnnealing: Annealing

Implementation Method 2

allowing oxygen to diffuse uniformly

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 3

grinding the substrate to adjust the thickness

Methodology Applied
Scientific EffectGrinding: Abrasion

Data Source

PatentEP3842574B1Semiconductor device and manufacturing method
Publication Date: 2024.03.27 FUJI ELECTRIC CO LTD
  • EP3842574B1 patent drawingFigure 1
  • EP3842574B1 patent drawingFigure 2
  • EP3842574B1 patent drawingFigure 3

AI summary

Provided is a semiconductor device comprising a semiconductor substrate containing oxygen. An oxygen concentration distribution in a depth direction of the semiconductor substrate has a high oxygen concentration part where an oxygen concentration is higher on a further upper surface-side than a center in the depth direction of the semiconductor substrate than in a lower surface of the semiconductor substrate. The high oxygen concentration part may have a concentration peak in the oxygen concentration distribution. A crystal defect density distribution in the depth direction of the semiconductor substrate has an upper surface-side density peak on the upper surface-side of the semiconductor substrate, and the upper surface-side density peak may be arranged within a depth range in which the oxygen concentration is equal to or greater than 50% of a peak value of the concentration peak.