Selective Epitaxial Growth Using Dichlorosilane at Low Temperature
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Solution Overview
Problem
Current methods for selective growth of silicon or silicon germanium films on silicon substrates require high temperatures for effective epitaxial growth, leading to thermal damage and increased thermal budgets, and involve cumbersome pre-cleaning processes.
Innovation Solution
A manufacturing method using a substrate processing apparatus where dichlorosilane and hydrogen gases are supplied at a temperature of 700° C. or less to remove natural oxide films and impurities, allowing selective epitaxial growth on silicon surfaces without forming silicon films on insulating films, thus reducing thermal damage and eliminating the need for pre-etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature reduction processing (800°C or more) is used to remove natural oxide film or impurities, then the reduction effect is sufficient, but thermal damage to substrate elements increases and thermal budget increases
Solution Approach 1:
The patent changes the temperature parameter from conventional high temperature (800°C or more) to low temperature (700°C or less) while using dichlorosilane gas as the reducing agent. This parameter change allows sufficient reduction of natural oxide films and impurities without causing thermal damage to substrate elements such as transistors or capacitors, and eliminates the need for pre-cleaning processes.
Solution Approach 2:
The patent introduces dichlorosilane gas as an intermediary reducing agent that enables effective oxide removal at lower temperatures compared to conventional hydrogen reduction methods. This intermediary substance facilitates the reduction reaction at 700°C or less, serving as a mediator between the thermal field and the oxide removal process.
2Reliability
If conventional hydrogen reduction method is used, then reduction processing can be performed, but pre-cleaning process by dilute hydrofluoric acid is required before reduction processing
Solution Approach 1:
The patent merges the oxide removal function into the epitaxial growth process itself by using dichlorosilane gas. The same gas that serves as the reducing agent for oxide removal also acts as the epitaxial growth source gas, combining what were previously separate steps (pre-cleaning and epitaxial growth) into a single integrated process.
Solution Approach 2:
Dichlorosilane gas serves as an intermediary that performs both reduction and epitaxial growth functions. This single substance replaces the need for separate pre-cleaning chemicals (dilute hydrofluoric acid) and subsequent epitaxial growth gases, simplifying the overall process flow.
3Reliability
If processing temperature is set high to remove natural oxide film or impurities, then reduction is effective, but silicon film or silicon nucleus may be formed on insulating film
Solution Approach 1:
The patent changes the temperature parameter to 700°C or less, which is sufficient for oxide removal with dichlorosilane gas but below the threshold for unwanted silicon film formation on insulating films. This precise temperature control maintains selective growth capability while achieving effective oxide removal.
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 method enables high-quality epitaxial growth at lower temperatures, reducing thermal damage and processing costs, while ensuring the epitaxial film grows only on the silicon surface, preventing harmful influences like deflection during selective growth.
Implementation Method 1
a pre-processing step of removing a natural oxide film or impurities formed on the silicon surface by supplying dichlorosilane gas and hydrogen gas into the processing chamber while maintaining a temperature of the substrate and the inside of the substrate processing chamber to a prescribed temperature of 700° C. or less
Implementation Method 2
by using a substrate processing apparatus for heating an atmosphere in the processing chamber and the substrate by a heating unit disposed outside of the processing chamber
Implementation Method 3
an epitaxial film is allowed to selectively grow only on the silicon surface
Implementation Method 4
supplying dichlorosilane gas and hydrogen gas into the processing chamber while maintaining a temperature of the substrate and the inside of the substrate processing chamber to a prescribed temperature of 700° C. or less
Data Source
AI summary
To provide a manufacturing method of a semiconductor device capable of performing a selective growth at a low temperature. A manufacturing method of a semiconductor device for placing in a processing chamber a substrate having at least a silicon surface and an insulating film surface on a surface; and allowing an epitaxial film to selectively grow only on the silicon surface by using a substrate processing apparatus for heating an atmosphere in the processing chamber and the substrate, using a heating unit disposed outside of the processing chamber, includes a substrate loading step of loading the substrate into the processing chamber; a pre-processing step of supplying dichlorosilane gas and hydrogen gas into the processing chamber while maintaining a temperature in the substrate processing chamber to a prescribed temperature of 700° C. or less, and removing a natural oxide film or impurities formed on the silicon surface; and a substrate unloading step of unloading the substrate to outside of the processing chamber.