Oxide Semiconductor Transistor Oxygen Profiling for Low Contact Resistance

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Solution Overview

Problem

Oxide semiconductor transistors face challenges in reducing contact resistance and managing oxygen concentration in the channel layer, which can lead to shifts in threshold voltage and increased contact resistance during subsequent processing steps.

Innovation Solution

The oxide semiconductor transistor design includes a substrate with first and second compound layers, a channel layer with varying oxygen concentrations, and electrodes positioned to facilitate a metal-oxygen reaction that reduces oxygen concentration in specific regions of the channel layer, thereby minimizing contact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a separate process is used to solve threshold voltage shift, then threshold voltage stability is improved, but contact resistance increases

Engineering Contradiction:

Improvethreshold voltage stabilityVSAvoidcontact resistance

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The channel layer is divided into multiple regions with different oxygen concentrations: a first region with higher oxygen concentration to stabilize threshold voltage, and second and third regions with lower oxygen concentration to reduce contact resistance. This spatial segmentation allows simultaneous optimization of both threshold voltage stability and contact properties without requiring separate corrective processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the channel layer are assigned different oxygen concentrations according to their functional requirements. The first region (gate-aligned area) has higher oxygen concentration for electrical stability, while the second and third regions (contact areas) have lower oxygen concentration for improved conductivity. This local quality differentiation resolves the contradiction by optimizing each region for its specific function.

Inventive Principle:

Principle #3Local quality

2Reliability

If oxygen concentration is reduced in channel layer, then contact resistance decreases, but threshold voltage shifts

Engineering Contradiction:

Improvecontact resistanceVSAvoidthreshold voltage stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The channel layer exhibits non-uniform oxygen concentration distribution: regions adjacent to source/drain electrodes have reduced oxygen concentration to minimize contact resistance, while the central region maintains higher oxygen concentration to stabilize threshold voltage. This localized quality control allows simultaneous optimization of both contact properties and electrical stability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The channel layer is segmented into functionally distinct zones with different oxygen concentrations. The segmentation creates a gradient structure where oxygen concentration varies spatially to meet different electrical requirements: low oxygen at contacts for conductivity, high oxygen in the middle for stability, eliminating the need for threshold voltage correction processes.

Inventive Principle:

Principle #1Segmentation

3Productivity

If channel length is reduced for high integration, then device density increases, but off-current increases

Engineering Contradiction:

Improvedevice integration densityVSAvoidoff-current

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The oxygen concentration parameter is changed spatially within the channel layer to optimize transistor performance. By creating regions of different oxygen concentrations, the invention maintains effective channel control even with reduced channel length, thereby suppressing off-current while preserving high integration density.

Inventive Principle:

Principle #35Parameter changes

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 design effectively reduces contact resistance between the electrodes and the channel layer, while maintaining a positive threshold voltage, thereby enhancing the operational speed and efficiency of memory devices incorporating these transistors.

Implementation Method 1

facilitate a metal-oxygen reaction that reduces oxygen concentration in specific regions of the channel layer

Methodology Applied

Scientific EffectMetal-oxygen reaction: Oxidation

Data Source

PatentUS20250072055A1Oxide semiconductor transistor, method of manufacturing the same, and memory device including oxide semiconductor transistor

Publication Date: 2025.02.27 SAMSUNG ELECTRONICS CO LTD

AI summary

The present disclosure relates to oxide semiconductor transistors, methods of manufacturing the same, and/or memory devices including the oxide semiconductor transistors. The oxide semiconductor transistor includes first and second compound layers provided on a substrate, a channel layer in contact with the first and second compound layers, a first electrode facing a portion of the channel layer, a second electrode facing the first compound layer with the channel layer therebetween, and a third electrode facing the second compound layer with the channel layer therebetween. An oxygen concentration of a region of the channel layer facing the first electrode is greater than that of the remaining regions of the channel layer. A buffer layer may further be provided between the channel layer and the second and third electrodes. The first and second compound layers may include oxygen and a metal.