Si Segregation Layer Formation on SiGe Channels via Hydrogen Plasma
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Solution Overview
Problem
The existing methods for forming a Si passivation film on a SiGe channel in semiconductor devices require high thermal loads or wet cleaning, which can damage the SiGe layer and lead to strain relaxation and reduced carrier mobility.
Innovation Solution
A plasma processing method is used to segregate silicon on the surface of the SiGe layer without high temperature heat treatment, employing hydrogen plasma processing to form an ultrathin Si segregation layer that protects the SiGe channel without damaging it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an epitaxial growth method is used to form a Si passivation film on a SiGe channel, then the interface characteristic between the SiGe channel and gate insulating film is improved, but high temperature heat treatment causes strain relaxation and reduces carrier mobility
Solution Approach 1:
The invention changes the temperature parameter from high temperature (750-850°C in epitaxial growth) to low temperature (room temperature or slightly elevated) plasma processing, thereby improving interface characteristics without causing strain relaxation that would reduce carrier mobility
Solution Approach 2:
The invention replaces the thermal field (heat treatment) with a plasma field (chemical field) to achieve Si surface segregation. Instead of using high temperature thermal diffusion, plasma processing enables Si segregation at low temperature through chemical reactions, thus avoiding strain relaxation while improving interface characteristics
2Quantity of substance
If high temperature heat treatment is applied to form Si passivation film, then the Si composition at the SiGe/silicon dioxide film interface is increased, but the strain in SiGe channel is relaxed and carrier mobility decreases
Solution Approach 1:
The invention replaces thermal diffusion with plasma-induced chemical segregation to increase Si composition at the interface without high temperature heat treatment, thereby maintaining strain in the SiGe channel and preserving carrier mobility
Solution Approach 2:
The invention changes the processing temperature from high temperature to low temperature, and uses plasma chemistry parameters (gas composition, power, pressure) to control Si segregation, achieving increased Si composition at interface without strain relaxation
3Ease of manufacture
If wet cleaning is performed on the SiGe channel surface, then the surface is cleaned, but the SiGe layer is damaged and strain relaxation occurs
Solution Approach 1:
The invention replaces wet chemical cleaning with plasma processing to clean and passivate the SiGe surface. Plasma cleaning removes contaminants without the mechanical and chemical damage caused by wet cleaning, maintaining SiGe layer integrity and preventing strain relaxation
Solution Approach 2:
The invention uses plasma (a controlled reactive environment) instead of liquid chemicals to clean the surface. The plasma environment allows for gentle cleaning and simultaneous passivation without the damaging effects of wet chemicals on the SiGe layer
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 allows for the formation of a Si segregation layer that enhances the SiGe channel's properties without causing strain relaxation or damage, improving carrier mobility and interface characteristics.
Implementation Method 1
performing plasma processing on the semiconductor substrate under a second condition to segregate silicon on the surface of the exposed silicon germanium layer
Implementation Method 2
segregate silicon on the surface of the exposed silicon germanium layer
Data Source
AI summary
A manufacturing process of a semiconductor device including a SiGe channel can form a Si segregation layer for protecting the SiGe channel without damaging the SiGe channel. A manufacturing method of a semiconductor device includes: a first step for performing plasma processing on a semiconductor substrate having a silicon layer and a silicon germanium layer formed on the silicon layer under a first condition to expose the silicon germanium layer; and a second step for performing plasma processing on the semiconductor substrate under a second condition to segregate silicon on the surface of the exposed silicon germanium layer. The silicon germanium layer or layers lying adjacent to the silicon germanium layer can be etched under the first condition, hydrogen plasma processing is performed under the second condition, and the first step and the second step are executed in series in the same processing chamber of a plasma processing apparatus.