Graded Film Electrical Depth Profiling via Anodic Oxidation

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Solution Overview

Problem

Existing electrical property depth profiling techniques are inadequate for accurately measuring the electrical properties of extremely thin semiconductor layers with varying compositions, especially in advanced device structures like SiGe alloys, due to their complexity and composition gradient.

Innovation Solution

A method involving anodic oxidation and measurement cycles with varying oxidation potentials and solutions to form oxide layers, allowing for precise determination of electrical properties through graded films using conversion factors and Van der Pauw equations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional anodic oxidation techniques are used for depth profiling, then measurement process can be implemented, but measurement precision is insufficient for extremely thin layers with composition gradients

Engineering Contradiction:

Improvedepth resolutionVSAvoidmeasurement accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent divides the continuous oxidation process into discrete depth segments by using multiple oxidation potentials. Each potential oxidizes a specific depth range, allowing separate measurement and analysis of different layers within the film. This segmentation enables precise depth resolution while maintaining measurement reliability through targeted analysis of each segment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different oxidation potentials locally to different depth regions of the film. By tailoring the oxidation conditions to match the specific composition and thickness of each layer, the method achieves high measurement precision for extremely thin layers while accounting for composition gradients throughout the structure.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If constant anodic current is applied to form oxide layers, then oxidation process can be controlled, but adaptability to compositionally graded films is insufficient

Engineering Contradiction:

Improvesuitability for graded filmsVSAvoidprocess complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent transitions from constant current to dynamically adjusted potential control. By varying the oxidation potential based on the expected composition and thickness at different depths, the method adapts to compositionally graded films. This dynamic approach increases versatility for analyzing complex structures while the systematic potential sequence keeps process complexity manageable.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the oxidation parameter from constant current to variable potential. This parameter change enables adaptation to different film compositions and thicknesses by selecting appropriate potentials for each oxidation step, making the technique versatile for graded films while maintaining controlled oxidation through established electrochemical relationships.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If repetitive oxidation and etching cycles are used, then depth profiling can be achieved, but productivity is reduced due to multiple processing steps

Engineering Contradiction:

Improvemeasurement efficiencyVSAvoiddepth profile accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent extracts and eliminates the chemical etching step from the conventional oxidation-etching cycle. By using selective oxidation at different potentials that directly exposes layers for measurement without requiring removal of oxide, the method improves productivity while maintaining depth profile accuracy through direct electrical measurements on the oxidized layers.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent establishes a continuous oxidation and measurement process without interruptive etching steps. Each oxidation potential continuously progresses the depth profiling while enabling immediate measurement, eliminating downtime and processing steps. This continuous action improves measurement efficiency while maintaining precision through uninterrupted depth progression.

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

Enables accurate depth profiling of electrical properties with sub-nanometer resolution, capturing composition gradients in complex semiconductor structures, enhancing device optimization.

Implementation Method 1

forming a first oxide layer by converting a first slice of the film into oxide at the test region

Methodology Applied

Scientific EffectAnodic oxidation: Oxidation

Implementation Method 2

electrochemically oxidizing the film in successive oxidation steps leaving behind residual films

Methodology Applied

Scientific EffectElectrochemical oxidation: Electrolysis

Implementation Method 3

measuring an electrical parameter by contacting the test site with electrical contact probes

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 4

measuring an electrical parameter by contacting the test site with electrical contact probes

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentUS20260005073A1Methods for electrical property depth profiling through films with graded composition

Publication Date: 2026.01.01 ACTIVE LAYER PARAMETRICS INC

AI summary

A method of obtaining a depth profile of an electrical property through a film with a composition varying as a function of depth is disclosed.