Nonvolatile Memory Device Using Excimer Laser Annealing and Nitrogen Plasma Planarization

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Solution Overview

Problem

High temperature deposition processes in flash memory devices can damage transparent glass substrates used in flat panel displays, leading to irregular surfaces and poor quality tunnel oxide layers, which deteriorate the program characteristics of nonvolatile semiconductor memory devices.

Innovation Solution

A method involving the formation of an amorphous silicon layer on a glass substrate, followed by Excimer laser annealing to crystallize the silicon layer, and nitrogen plasma treatment to planarize its surface, allowing for the deposition of a uniform ONO layer and metal gate electrode at low temperatures, enhancing the stability and yield of nonvolatile memory devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high temperature thermal oxidation is used to form ONO structure, then dielectric layer quality is improved, but glass substrate is damaged and melted

Engineering Contradiction:

Improvedielectric layer qualityVSAvoidglass substrate damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the temperature parameter from high temperature thermal oxidation to low temperature plasma oxidation, allowing the formation of quality dielectric layers without damaging the glass substrate. The plasma process achieves adequate oxidation at temperatures compatible with glass substrates.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal field (high temperature thermal oxidation) with a plasma field (low temperature plasma oxidation). This substitution allows dielectric layer formation through chemical reactions in plasma environment rather than thermal diffusion, avoiding substrate damage while maintaining layer quality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Stability of the object's composition

If Excimer laser annealing is used to crystallize amorphous silicon, then crystallized polycrystalline silicon layer is formed, but upper surface becomes irregular

Engineering Contradiction:

Improvecrystallized silicon layer formationVSAvoidsurface irregularity

Core Design Contradiction:

Stability of the object's compositionVSShape

Solution Approach 1:

The patent introduces a plasma treatment process as an intermediary step between laser annealing and tunnel oxide formation. This plasma treatment planarizes the irregular surface of crystallized silicon, creating a smooth intermediate surface that enables subsequent uniform tunnel oxide layer formation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Temperature

If tunnel oxide layer is formed on irregular polycrystalline silicon surface, then low temperature process is achieved, but tunnel oxide layer quality deteriorates

Engineering Contradiction:

Improveprocess temperatureVSAvoidtunnel oxide layer quality

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent performs preliminary plasma treatment to planarize the silicon surface before forming the tunnel oxide layer. This preliminary action creates a smooth surface foundation, ensuring that subsequent low temperature oxidation produces uniform quality tunnel oxide layers despite the low temperature constraint.

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

This approach results in a nonvolatile memory device with improved program characteristics and stability, enabling the formation of high-quality tunnel oxide layers with uniform thickness, suitable for integration in flat panel displays with low power consumption.

Implementation Method 1

annealing the amorphous silicon layer by using an Excimer laser to form a crystallized silicon layer

Methodology Applied

Scientific EffectLaser annealing: Laser

Implementation Method 2

performing a nitrogen plasma treatment for the crystallized silicon layer to planarize an upper surface of the crystallized silicon layer

Methodology Applied

Scientific EffectPlasma treatment: Plasma

Implementation Method 3

forming an ONO layer on the nitrogen plasma-treated crystallized silicon layer

Methodology Applied

Scientific EffectLow temperature deposition: Deposition (physical)

Data Source

PatentUS8216900B2Nonvolatile memory device, method of manufacturing the nonvolatile memory device, and method of manufacturing flat panel display device provided with the nonvolatile memory device

Publication Date: 2012.07.10 MARVELL ASIA PTE LTD

AI summary

Provided are a nonvolatile memory device, a method of manufacturing the nonvolatile memory device, and a method of manufacturing a flat panel display device provided therein with the nonvolatile memory device. According to an embodiment, an amorphous silicon layer is formed on a substrate, and then annealed by using an Excimer laser to form a crystallized silicon layer. A nitrogen plasma treatment is performed for the crystallized silicon layer to planarize an upper surface of the crystallized silicon layer. An ONO layer is formed on the nitrogen plasma-treated crystallized silicon layer. A metal layer is formed on the ONO layer. The metal layer, the ONO layer and the nitrogen plasma-treated crystallized silicon layer are patterned.