Polycrystallization of Amorphous Semiconductor Film Using Ozone Water

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Solution Overview

Problem

The conventional method for polycrystallizing amorphous semiconductor films requires multiple processes, including removal of the natural oxide film and subsequent re-oxidation, which reduces production efficiency and stability of thin film transistors.

Innovation Solution

A polycrystallization method that cleans the natural oxide film using ozone water to introduce oxygen uniformly, allowing for polycrystallization to occur without completely removing the natural oxide film, thereby reducing the number of processes and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the natural oxide film is completely removed with hydrofluoric acid and re-formed through oxidation, then stable polycrystalline semiconductor film can be obtained, but the number of processes increases and production efficiency decreases

Engineering Contradiction:
Improvestability of thin film transistorVSAvoidproduction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention extracts and removes the natural oxide film from the amorphous semiconductor film surface using hydrofluoric acid in the pretreatment process, then selectively re-forms a controlled oxide film during laser irradiation by controlling oxygen concentration in the atmosphere, thereby eliminating the need for separate re-oxidation steps and reducing total process time

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention performs preliminary oxidation of the amorphous semiconductor film surface by irradiating with a laser in an oxygen-rich atmosphere before polycrystallization, so that the oxide film is already formed and ready to provide oxygen during the subsequent polycrystallization step, eliminating the need for separate oxidation and polycrystallization steps

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If the natural oxide film is completely removed in the pretreatment process, then polycrystallization can proceed, but additional oxidation steps are required in the crystallization process

Engineering Contradiction:
Improvepolycrystallization processVSAvoidnumber of processes
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention merges the oxidation step and polycrystallization step into a single integrated process by controlling the laser irradiation conditions and oxygen concentration in the atmosphere simultaneously, so that the oxide film formation and polycrystallization occur together during laser irradiation, reducing the total number of separate processes

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention dynamically adjusts the oxygen concentration in the atmosphere during laser irradiation - starting with high oxygen concentration to form the oxide film, then reducing oxygen concentration to enable polycrystallization - allowing the process conditions to change continuously to achieve both oxidation and polycrystallization in one step

Inventive Principle:
Principle #15Dynamics

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 simplifies the process by maintaining the natural oxide film, ensuring stable polycrystalline semiconductor film formation and enhancing production efficiency by eliminating the need for hydrofluoric acid treatment and additional oxidation steps.

Implementation Method 1

cleaning the natural oxide film while leaving the natural oxide film on the surface... cleaning the natural oxide film using ozone water to introduce oxygen uniformly

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

the amorphous semiconductor film is irradiated with a laser in the atmosphere of oxygen at a comparatively high concentration

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 3

the amorphous semiconductor film is polycrystallized

Methodology Applied
Scientific EffectPolycrystallization: Crystallisation

Data Source

PatentUS9384965B2Polycrystallization method
Publication Date: 2016.07.05 MAGNOLIA WHITE CORP

AI summary

According to one embodiment, provided is a polycrystallization method for polycrystallizing an amorphous semiconductor film that has a natural oxide film on the surface. The polycrystallization method includes a step of cleaning the natural oxide film while leaving the natural oxide film on the surface of the amorphous semiconductor film, and a step of polycrystallizing the amorphous semiconductor film in the state where the natural oxide film is left.