Selective Deposition of Doped Semiconductor Layers

Solution Overview

Problem

Conventional methods for scaling semiconductor devices face challenges in enhancing carrier mobility and reducing contact resistance, particularly for p-type MOS devices due to low boron solubility in silicon germanium films, leading to high contact resistivity and dopant clustering issues during high-temperature anneal processes.

Innovation Solution

A selective deposition method for doped semiconductor layers is developed, allowing for the formation of p-type or n-type doped Group IV semiconductor layers with low contact resistance at temperatures below 600°C without annealing, using a substrate with distinct material areas and alternating cycles of precursor and etchant flow in a reaction chamber, enabling the deposition of layers with specific dopant concentrations and compositions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high boron concentration is used in silicon germanium films to reduce contact resistance, then contact resistivity decreases, but boron solubility limits prevent achieving sufficiently high concentrations

Engineering Contradiction:

Improvecontact resistanceVSAvoidboron concentration

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the deposition temperature parameter to below 600°C and uses alternating precursor and etchant flow cycles to achieve high boron concentration (exceeding solid solubility limits) in silicon germanium films, thereby reducing contact resistance to below 0.3 mΩ-cm while maintaining film quality

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies selective deposition to create locally doped regions with high boron concentration only where needed (source and drain regions), while maintaining different material compositions in different areas of the substrate through spatially selective precursor and etchant delivery

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If high-temperature anneal process is used to improve dopant solubility and reduce contact resistance, then dopant concentration increases, but dopant clustering occurs

Engineering Contradiction:

Improvedopant concentrationVSAvoiddopant distribution uniformity

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent performs preliminary doping during the deposition process itself rather than relying on subsequent annealing, incorporating high dopant concentrations directly into the film during low-temperature deposition below 600°C, thereby achieving high dopant concentration without the clustering that would result from high-temperature annealing

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the thermal annealing mechanism with a chemical vapor deposition mechanism using alternating precursor and etchant flow cycles, enabling dopant incorporation at low temperatures through chemical reactions rather than thermal diffusion, thus avoiding dopant clustering

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If conventional scaling techniques are used to improve device speed and density, then device performance increases, but challenges arise in maintaining carrier mobility and contact resistance at future technology nodes

Engineering Contradiction:

Improvedevice densityVSAvoidcarrier mobility

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the deposition temperature parameter to below 600°C and uses alternating precursor and etchant flow cycles to achieve high boron concentration (exceeding solid solubility limits) in silicon germanium films, thereby reducing contact resistance to below 0.3 mΩ-cm while maintaining film quality

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies selective deposition to create locally doped regions with high boron concentration only where needed (source and drain regions), while maintaining different material compositions in different areas of the substrate through spatially selective precursor and etchant delivery

Inventive Principle:

Principle #3Local quality

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 low contact resistance and maintains structural integrity of deposited layers, improving carrier mobility and reducing dopant clustering, thereby enhancing semiconductor device performance.

Implementation Method 1

selectively depositing a first doped semiconductor layer overlying the first material; and selectively depositing a second doped semiconductor layer overlying the first doped semiconductor layer

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Implementation Method 2

an etchant can be flowed during the step of selectively depositing the first doped semiconductor layer

Methodology Applied

Scientific EffectChemical Etching:

Data Source

PatentUS11637014B2Methods for selective deposition of doped semiconductor material

Publication Date: 2023.04.25 ASM IP HLDG BV

AI summary

Methods and systems for selectively depositing material, such as doped semiconductor material, are disclosed. An exemplary method includes providing a substrate, comprising a first area comprising a first material and a second area comprising a second material, selectively depositing a first doped semiconductor layer overlying the first material relative to the second material and selectively depositing a second doped semiconductor layer overlying the first doped semiconductor layer relative to the second material.