Memory Gate Work Function Testing via Charge Injection Capacitance

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Solution Overview

Problem

Existing methods for determining the effective work function of a gate electrode in a memory device require optical apparatuses and cannot accurately measure the work function under conditions where the gate electrode is in contact with a blocking insulation layer, leading to challenges in sample size reduction and sensitivity to surface contamination.

Innovation Solution

A test device comprising a test memory device with a semiconductor substrate, insulation layer, and charge injection electrode is used to determine the effective work function through capacitance changes induced by voltage application, allowing for non-optical measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If optical methods (photoelectron spectroscopy, inverse photoelectron spectroscopy) are used to measure effective work function, then measurement capability is achieved, but sample size requirements increase and surface contamination sensitivity worsens

Engineering Contradiction:

Improveeffective work function measurementVSAvoidsurface contamination sensitivity

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces optical measurement methods with an electrical measurement method. Instead of using photoelectron spectroscopy or inverse photoelectron spectroscopy that require light interaction, the invention uses a test device that applies voltage to a charge injection electrode to inject charges into the memory device and measures capacitance changes. This electrical approach eliminates the need for large samples and reduces sensitivity to surface contamination.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from optical properties (photoelectron emission) to electrical properties (capacitance). By measuring capacitance changes when voltage is applied to the charge injection electrode, the system determines effective work function through electrical characteristics rather than optical characteristics, enabling smaller sample sizes and reduced contamination sensitivity.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If optical measurement methods are used, then effective work function can be determined, but device complexity and measurement setup burden increase

Engineering Contradiction:

Improveeffective work function determinationVSAvoidoptical apparatus requirements

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent substitutes complex optical apparatus with a simple electrical measurement system. The test device includes a charge injection electrode, insulation layer, and capacitance measurement capability, eliminating the need for sophisticated optical equipment like photoelectron spectroscopy systems or inverse photoelectron spectroscopy systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the measurement function from complex optical systems and implements it through a simplified electrical test device. By taking out the essential measurement capability and implementing it through voltage application and capacitance measurement, the system removes the burden of complex optical apparatus while maintaining measurement functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

3Measurement precision

If vacuum conditions are used to prevent surface contamination, then measurement accuracy improves, but measurement process complexity and time requirements increase

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidmeasurement process time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces vacuum-based protection with an electrical measurement approach that is inherently less sensitive to surface contamination. By measuring capacitance changes through voltage application to the charge injection electrode, the system determines effective work function without requiring vacuum conditions, thereby reducing measurement process time and complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The method enables accurate and simple determination of the effective work function of the gate electrode while maintaining contact with the blocking insulation layer, improving accuracy and reliability without the need for optical apparatuses.

Implementation Method 1

A capacitance change of the test memory device in accordance with a voltage applied to the charge injection electrode may be measured to determine the effective work function of the gate electrode layer

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS12467893B2Test device for determining an effective work function, method of manufacturing the same and method of determining an effective work function

Publication Date: 2025.11.11 SK HYNIX INC

AI summary

A test device may include a test memory device, an insulation layer and a charge injection electrode. The test memory device may include a memory layer and a gate electrode layer on a semiconductor substrate. The insulation layer may be arranged on the test memory device. The charge injection electrode may be arranged on the insulation layer to inject a charge into the test memory device based on a voltage.