Threshold Switching Semiconductor Channel Structure for Low-Temperature Processing

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Solution Overview

Problem

The BEOL process for integrated circuits faces challenges with high-temperature dopant activation, which can damage metal wiring and reduce circuit performance, while alternative channel materials like oxide semiconductors and two-dimensional materials suffer from low carrier mobility and poor uniformity.

Innovation Solution

A semiconductor structure incorporating a channel structure made of threshold switching materials, such as ovonic threshold switching materials or mixed-ionic-electronic-conduction materials, which can be fabricated at lower process temperatures (≤500°C) and maintain high carrier mobility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high temperature (600°C to 1000°C) is used to activate dopants in doped silicon channel, then carrier mobility is improved, but metal wiring in integrated circuits is damaged

Engineering Contradiction:

Improvecarrier mobilityVSAvoiddamage to metal wiring

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the temperature parameter from high temperature (600-1000°C) to low temperature (≤500°C) processing by using threshold switching materials, thereby avoiding damage to metal wiring while maintaining acceptable carrier mobility through material substitution rather than thermal activation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material strategies by using threshold switching materials that combine properties of phase change materials, ovonic threshold switching materials, or mixed ionic-electronic conduction materials to achieve both low processing temperature and high carrier mobility, resolving the contradiction between temperature requirements and material performance

Inventive Principle:

Principle #40Composite materials

2Temperature

If oxide semiconductor is used as channel material to reduce process temperature, then metal wiring is protected from damage, but carrier mobility becomes low

Engineering Contradiction:

Improveprocess temperatureVSAvoidcarrier mobility

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent uses composite or composite-like threshold switching materials (phase change materials, ovonic threshold switching materials, mixed ionic-electronic conduction materials) that combine the low processing temperature advantage of oxide semiconductors with the high carrier mobility typically requiring high temperatures, thereby resolving the contradiction

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameter from conventional oxide semiconductors to advanced threshold switching materials, which fundamentally alter the electrical transport properties to achieve high carrier mobility at low processing temperatures

Inventive Principle:

Principle #35Parameter changes

3Temperature

If two-dimensional material is used as channel material to reduce process temperature, then metal wiring is protected from damage, but uniformity becomes poor

Engineering Contradiction:

Improveprocess temperatureVSAvoiduniformity

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent employs composite threshold switching material systems that can be deposited using conventional thin-film techniques (such as sputtering, CVD, or ALD) which provide superior uniformity compared to two-dimensional material transfer methods, while maintaining low processing temperatures

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent uses amorphous or nanocrystalline threshold switching materials that can be readily deposited and processed without requiring the complex, non-uniform two-dimensional material transfer processes, accepting some material imperfections that are easily remedied through standard semiconductor processing

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 semiconductor structure enables high current flow through the channel structure without damaging other components, achieving high carrier mobility and maintaining good electrical performance even at lower process temperatures.

Implementation Method 1

The threshold switching material includes an ovonic threshold switching material, a mixed-ionic-electronic-conduction material, a phase change material

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 2

the mixed-ionic-electronic-conduction material includes CuSbGeTe, CuSbGeSTe, or a combination thereof

Methodology Applied

Scientific EffectMixed ionic-electronic conduction:

Data Source

PatentUS20250169385A1Semiconductor structure and operating method thereof

Publication Date: 2025.05.22 MACRONIX INTERNATIONAL CO LTD

AI summary

A semiconductor structure includes a gate, a channel structure, a gate insulating layer, a source, and a drain. The channel structure includes a threshold switching material, in which the channel structure includes a layered channel, a columnar channel, or a plurality of nanosheet channels. The gate insulating layer is disposed between the gate and the channel structure. The source is in direct contact with the channel structure. The drain is in direct contact with the channel structure.