Pulsed CVD Deposition of Complex Nitride Films
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Solution Overview
Problem
Current methods for depositing nitride films, such as CVD and ALD, face challenges with high chlorine incorporation and low deposition rates, particularly at higher temperatures, limiting the efficiency and throughput in semiconductor manufacturing.
Innovation Solution
A pulsed Chemical Vapor Deposition (CVD) method using temporally separated pulses of metal halide precursors and continuous or pulsed nitrogen-containing precursors, such as NH3, within a temperature range of 300° C. to 700° C., to induce thermally activated reactions and achieve higher deposition rates and reduced chlorine content in nitride films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CVD is used to deposit nitride films at high temperatures, then deposition rates improve, but chlorine incorporation increases
Solution Approach 1:
The patent employs periodic pulsing of metal halide precursor gases into the reaction chamber, alternating with purge cycles. This periodic introduction allows controlled reaction at elevated temperatures while preventing excessive chlorine incorporation through timed exposure and removal cycles, resolving the contradiction between deposition rate and chlorine content
Solution Approach 2:
The patent utilizes temperature modulation within the CVD process, heating the substrate to temperatures between 200-450°C during precursor exposure and utilizing thermal field adjustments during purge cycles. This parameter change enables faster deposition kinetics at higher temperatures while controlling chlorine incorporation through temperature-cycled reaction conditions
2Manufacturing precision
If ALD is used to deposit nitride films, then film uniformity and control improve, but deposition rates decrease
Solution Approach 1:
The patent segments the continuous CVD process into discrete pulsing cycles of metal halide precursor introduction followed by purge cycles. This segmentation maintains the controlled, sequential nature of ALD for film uniformity while allowing faster overall deposition by eliminating the strict waiting periods required in conventional ALD, thus improving productivity without sacrificing precision
3Object-generated harmful factors
If metal-organic precursors are used to prevent chlorine incorporation, then chlorine content decreases, but deposition temperatures must be lowered
Solution Approach 1:
The patent introduces chlorine-scavenging agents or modifying precursors that act as intermediaries between the metal halide precursor and the substrate. These intermediaries preferentially react with excess chlorine or modify the precursor chemistry to reduce chlorine incorporation, allowing the process to maintain higher deposition temperatures without the harmful effects of excessive chlorine in the film
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
This approach results in significant improvements in film thickness and uniformity, reducing chlorine incorporation and increasing deposition rates, enabling the formation of high-quality nitride films with enhanced properties suitable for semiconductor applications.
Implementation Method 1
heating the substrate in the reaction chamber to a temperature between about 300° C. and about 700° C.
Implementation Method 2
A first metal halide precursor is flowed into the reaction chamber in temporally separated pulses and a second metal halide precursor is also flowed into the reaction chamber in temporally separated pulses. A nitrogen-containing precursor is also flowed into the reaction chamber.
Data Source
AI summary
Methods are provided for pulsed chemical vapor deposition (CVD) of complex nitrides, such as ternary metal nitrides. Pulses of metal halide precursors are separated from one another and nitrogen-containing precursor is provided during the metal halide precursor pulses as well as between the metal halide precursor pulses. Two different metal halide precursors can be provided in simultaneous pulses, alternatingly, or in a variety of sequences. The nitrogen-containing precursor, such as ammonia, can be provided in pulses simultaneously with the metal halide precursors and between the metal halide precursors, or continuously throughout the deposition. Temperatures can be kept between about 300° C. and about 700° C.