SiGe Etching by Selective Oxidation Across Germanium Gradients

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Solution Overview

Problem

Conventional etching processes struggle to selectively remove one silicon-and-germanium-containing material relative to another in semiconductor manufacturing, particularly in gate-all-around (GAA) transistors, leading to undesirable etching of epitaxial silicon-and-germanium-containing material.

Innovation Solution

A method involving selective oxidation of silicon-and-germanium-containing materials with varying germanium concentrations, followed by etching, where materials with higher germanium concentrations are preferentially oxidized, making them more resistant to etching, allowing selective removal of materials with lower germanium concentrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional etching processes are used, then etching speed is maintained, but selectivity between different germanium concentration materials deteriorates

Engineering Contradiction:

Improveetching selectivityVSAvoidetching speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies preliminary oxidation to the silicon-germanium-containing material before etching. By pre-oxidizing the material with higher germanium concentration, a protective oxide layer is formed that enables subsequent selective etching. This preliminary action modifies the material properties in advance, allowing the etch process to distinguish between different germanium concentrations and achieve high selectivity without sacrificing etching speed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the chemical state of the silicon-germanium-containing material by controlling oxidation parameters. By adjusting oxidation conditions (temperature, time, atmosphere), the material undergoes phase or state changes that create differential reactivity to the etchant. This parameter change enables the etching process to selectively remove material based on germanium concentration while maintaining overall etching efficiency.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If wet etching is used, then etching uniformity is improved, but penetration into constrained trenches deteriorates

Engineering Contradiction:

Improveetching uniformityVSAvoidtrench penetration depth

Core Design Contradiction:

Manufacturing precisionVSLength of moving object

Solution Approach 1:

The patent replaces wet chemical etching with a plasma-based etching process. Plasma etching uses reactive species in a controlled plasma environment to achieve both uniform etching and deep trench penetration. The plasma process substitutes the liquid chemical mechanism with a gas-phase reactive ion mechanism that can access constrained geometries while maintaining uniformity through controlled plasma distribution.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Length of moving object

If dry plasma etching is used, then trench penetration is improved, but substrate damage through electric arcs worsens

Engineering Contradiction:

Improvetrench penetration depthVSAvoidsubstrate damage

Core Design Contradiction:

Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent carefully controls plasma process parameters including power, pressure, gas composition, and temperature to prevent electric arc formation. By optimizing these parameters, the plasma etching process achieves deep trench penetration without the harmful electric arcs that cause substrate damage. The parameter changes transform the plasma process from a damaging high-power regime to a controlled low-damage regime that maintains etching effectiveness.

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

The method achieves selective etching of silicon-and-germanium-containing materials with a selectivity of greater than 40:1, ensuring precise removal of targeted materials while preserving others, thereby improving the quality of semiconductor devices.

Implementation Method 1

contacting the substrate with the oxygen-containing precursor. The contacting may oxidize at least a portion of the second layer of silicon-and-germanium-containing material

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

contacting the substrate with the etchant precursor. The contacting may etch the first layer of silicon-and-germanium-containing material

Methodology Applied

Scientific EffectChemical etching:

Data Source

PatentUS20260005030A1Selective etching between silicon-and-germanium-containing materials with varying germanium concentrations

Publication Date: 2026.01.01 APPLIED MATERIALS INC

AI summary

Exemplary semiconductor processing methods may include providing a pre-treatment precursor to a processing region of a semiconductor processing chamber. A first layer of silicon-and-germanium-containing material and a second layer of silicon-and-germanium-containing material may be disposed on a substrate housed within the processing region. The methods may include contacting the substrate with the pre-treatment precursor to remove the native oxide. The methods may include providing an oxygen-containing precursor to the processing region. The methods may include contacting the substrate with the oxygen-containing precursor to oxidize at least a portion of the second layer. The methods may include providing an etchant precursor to the processing region. The methods may include contacting the substrate with the etchant precursor to etch the first layer of silicon-and-germanium-containing material.