Germanium Film Formation via Aminosilane Buffer Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods fail to achieve a germanium (Ge) film with a high Ge concentration and good surface roughness necessary for next-generation semiconductor integrated circuit devices, as existing Ge or Ge-rich SiGe films exhibit surface roughness beyond the nanometer scale required for high-speed operation.
Innovation Solution
A method involving the supply of aminosilane-based gases, high-order silane gases, and Ge source gases in a processing chamber, with controlled temperature and gas supply sequences, to form Ge-rich SiGe films with Ge concentrations over 70% and surface roughness of 1 nm or less, utilizing a film forming apparatus with a heating device, exhaust system, and controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ge or Ge-rich SiGe film is formed on underlayer such as SiO2, SiN, C, metal or the like, then high carrier mobility is achieved, but surface roughness exceeds nanometer scale
Solution Approach 1:
The patent applies preliminary action by forming a buffer layer (such as Ge-rich SiGe layer or amorphous Ge layer) before forming the final Ge channel layer. This buffer layer prepares the surface in advance to ensure both high Ge concentration and nanometer-level surface roughness, resolving the contradiction between carrier mobility and surface quality.
Solution Approach 2:
The patent changes process parameters including forming the buffer layer at specific temperatures (700-900°C for Ge-rich SiGe, or lower temperatures for amorphous Ge), controlling Ge concentration gradients, and adjusting film thickness parameters. These parameter changes enable achieving both high carrier mobility and surface roughness within 1 nm or less.
2Reliability
If Ge concentration is increased to achieve high carrier mobility, then electron mobility and hole mobility improve, but surface roughness deteriorates
Solution Approach 1:
The patent applies local quality by creating different Ge concentration zones: a buffer layer with lower Ge concentration (or Ge-rich SiGe composition) near the underlayer, and a top Ge layer with high Ge concentration (90-100%). Each zone has optimized local properties - the buffer layer ensures surface quality while the top layer provides high carrier mobility.
Solution Approach 2:
The patent uses composite material structure combining Ge-rich SiGe or amorphous Ge buffer layer with crystalline Ge channel layer. This composite approach allows the buffer layer to provide surface smoothness while the Ge layer provides high carrier mobility, resolving the contradiction between Ge concentration and surface roughness.
3Manufacturing precision
If surface roughness is reduced to nanometer level, then carrier scattering is minimized, but difficulty in forming Ge film on underlayer increases
Solution Approach 1:
The patent introduces an intermediary buffer layer (Ge-rich SiGe or amorphous Ge) between the underlayer and the Ge channel layer. This intermediary layer mediates the interface between different materials, enabling formation of high-quality Ge film with nanometer-level surface roughness while simplifying the overall manufacturing process.
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 effectively reduces surface roughness to nanometer levels, enhancing carrier mobility and suitability for high-speed semiconductor applications, while maintaining high Ge concentration, thus addressing the limitations of existing technologies.
Implementation Method 1
supplying an aminosilane-based gas into a processing chamber in which the target object is loaded; supplying a high-order silane-based gas of disilane or higher into the processing chamber; and supplying a Ge source gas into the processing chamber
Implementation Method 2
a process temperature in supplying the Ge source gas is set to fall within a range from a temperature, at which the Ge source gas is thermally decomposed or higher
Data Source
AI summary
There is provided a method of forming a germanium (Ge) film on a surface of a target object, which includes: supplying an aminosilane-based gas into a processing chamber in which the target object is loaded; supplying a high-order silane-based gas of disilane or higher into the processing chamber; and supplying a Ge source gas into the processing chamber. A process temperature in supplying the Ge source gas is set to fall within a range from a temperature, at which the Ge source gas is thermally decomposed or higher, to 300 degrees C. or less.