Selective MoS2 Deposition for Continuous 2D Semiconductor Layers
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Solution Overview
Problem
Challenges exist in the direct deposition of molybdenum-containing materials like MoS2 for 2D transition metal dichalcogenides in semiconductor devices due to issues with layer continuity and integration.
Innovation Solution
A method involving a cyclic deposition process using gas-phase molybdenum and chalcogen precursors, such as MoO2Cl2 and H2S, at controlled temperatures (350° C. to 650° C.) to form molybdenum dichalcogenides like MoS2, MoSe2, and MoTe2, with selective deposition on specific surfaces and optional etch-back steps for precise thickness control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If direct deposition method is used to deposit molybdenum-containing materials, then deposition process is simple, but layer continuity is poor
Solution Approach 1:
The deposition process is divided into multiple cyclic steps: first introducing molybdenum precursor to form MoO3 layer, then introducing chalcogen precursor to form MoS2 layer, followed by reduction step. This segmentation of the deposition process into discrete cyclic steps enables precise control over layer formation and improves layer continuity while maintaining process simplicity
Solution Approach 2:
The patent employs periodic cyclic deposition where precursors are introduced alternately in repeated cycles. Each cycle consists of molybdenum precursor introduction, chalcogen precursor introduction, and reduction steps. This periodic action allows controlled buildup of continuous 2D layers with precise thickness control, resolving the contradiction between process simplicity and layer continuity
2Manufacturing precision
If cyclic deposition process is used to improve layer continuity, then layer continuity is improved, but process complexity increases
Solution Approach 1:
Multiple deposition functions are merged into a single cyclic process chamber. The molybdenum precursor deposition, chalcogen precursor deposition, and reduction steps are combined in one integrated cyclic sequence, eliminating the need for multiple separate chambers or complex equipment while achieving continuous layer formation
Solution Approach 2:
The patent controls deposition parameters including temperature (350-650°C), precursor flow rates, and cycle timing to optimize layer continuity. By adjusting these parameters within specific ranges, high-quality continuous layers are achieved without requiring overly complex process equipment
3Reliability
If high temperature deposition is used to improve material quality, then material quality is improved, but energy consumption increases
Solution Approach 1:
The cyclic deposition process maintains continuous useful action by keeping the substrate at optimal temperature throughout the cycle. Heating is sustained during precursor introduction and reaction steps, ensuring high material quality while minimizing total energy consumption by avoiding repeated heating cycles
Solution Approach 2:
The patent specifies temperature ranges (350-650°C) that balance material quality and energy consumption. Within this range, high-quality MoS2 layers are formed with controlled crystal structure while energy consumption is kept manageable through optimized heating duration and temperature selection
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
Enables the deposition of ultra-thin, uniform molybdenum dichalcogenide layers with high selectivity and controlled thickness, suitable for advanced semiconductor applications, including nanoelectronics and optoelectronics.
Implementation Method 1
contacting the first surface with a gas-phase molybdenum precursor and contacting the first surface with a gas-phase chalcogen precursor
Implementation Method 2
a molybdenum precursor source constructed and arranged to contain and vaporize a molybdenum precursor
Implementation Method 3
a chalcogen precursor source constructed and arranged to contain and vaporize a chalcogen precursor
Data Source
AI summary
The disclosure relates to methods of depositing a molybdenum dichalcogenide on a surface of a semiconductor substrate from a gas phase. The methods utilize an oxygen and halogen comprising molybdenum precursor and, in some embodiments, the deposition methods may be selective. The methods may be cyclic deposition methods, in particular atomic layer deposition methods. The disclosure further relates to a molybdenum dichalcogenide layer deposited according to the methods herein, as well as to semiconductor processing assemblies arranged to execute said methods.