Amorphous Silicon Deposition Using Silicon Iodide Surface Selectivity

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Solution Overview

Problem

Existing methods for depositing amorphous silicon films require complex patterning and etch processes, which are time-consuming and costly, especially as device feature sizes decrease, and there is a need for precise selective deposition on metallic nitride versus metallic oxide surfaces.

Innovation Solution

A method involving a silicon iodide precursor in a controlled environment, such as a chemical vapor deposition chamber, heats the substrate to a specific temperature to selectively deposit amorphous silicon on metallic nitride surfaces relative to metallic oxide surfaces, using a silicon iodide precursor without plasma excitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If blanket deposition and photolithography patterning are used to deposit amorphous silicon film, then the amorphous silicon film can be deposited on the substrate, but the process becomes complex, time-consuming, and expensive

Engineering Contradiction:

Improveselectivity of amorphous silicon depositionVSAvoidcomplexity of patterning process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating different surface properties in different regions of the substrate. Specifically, metallic nitride surfaces are prepared to have high affinity for amorphous silicon deposition, while metallic oxide surfaces are prepared to have low affinity, enabling selective deposition without photolithography. This is achieved through controlled surface treatments that create local variations in surface chemistry and reactivity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs self-service by using the substrate's own surface properties to guide the deposition process. The metallic nitride and metallic oxide surfaces inherently provide the selectivity needed for patterned amorphous silicon deposition. The surface preparation steps create self-assembled surface characteristics that automatically direct where deposition occurs, eliminating the need for external patterning tools.

Inventive Principle:

Principle #25Self-service

2Manufacturing precision

If photolithography and etch steps are used to pattern amorphous silicon film, then the desired pattern can be achieved, but the process becomes time-consuming and expensive

Engineering Contradiction:

Improveprecision of pattern formationVSAvoidtime for patterning process

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by preparing the substrate surface before deposition to pre-determine where amorphous silicon will deposit. Surface treatment steps are performed in advance to create regions with different deposition affinities. This preliminary surface preparation eliminates the need for subsequent photolithography and etching steps, as the pattern is essentially pre-defined by the surface properties.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If selective deposition is used to deposit amorphous silicon only on desired areas, then subsequent patterning steps are eliminated, but achieving high selectivity between metallic nitride and metallic oxide surfaces is challenging

Engineering Contradiction:

Improveefficiency of deposition processVSAvoidselectivity between different surfaces

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by controlling surface chemical and physical parameters to achieve selective deposition. Specifically, surface treatment parameters such as oxidation state, surface energy, and chemical composition are adjusted to create a large difference in deposition affinity between metallic nitride and metallic oxide surfaces. Temperature, pressure, and precursor flow rates are also optimized to enhance selectivity.

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

Achieves high selectivity and precision in depositing amorphous silicon films, reducing the need for complex patterning steps and enabling self-aligned hardmask materials for semiconductor devices with minimal impurities and excellent step coverage.

Implementation Method 1

contacting the substrate with silicon iodide precursor; and selectively depositing the amorphous silicon film on the metallic nitride surface relative to the metallic oxide surface

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Implementation Method 2

heating the substrate to a deposition temperature; contacting the substrate with silicon iodide precursor

Methodology Applied

Scientific EffectThermal decomposition: Thermolysis

Data Source

PatentUS20260015716A1Methods for selectively depositing an amorphous silicon film on a substrate

Publication Date: 2026.01.15 ASM IP HLDG BV

AI summary

A method for selectively depositing an amorphous silicon film on a substrate comprising a metallic nitride surface and a metallic oxide surface is disclosed. The method may include; providing a substrate within a reaction chamber, heating the substrate to a deposition temperature, contacting the substrate with silicon iodide precursor, and selectively depositing the amorphous silicon film on the metallic nitride surface relative to the metallic oxide surface. Semiconductor device structures including an amorphous silicon film deposited by selective deposition methods are also disclosed.