(110) Silicon Substrate Defect Reduction via Epitaxial Deposition
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Solution Overview
Problem
The manufacturing of high-quality silicon substrates with (110) orientation is hindered by surface defects such as Crystal Oriented Pits (COPs) and oxygen precipitations, leading to costly and low-yield crystal growth processes, and (110) oriented silicon substrates are prone to roughness and defects during heat treatment.
Innovation Solution
A method involving the epitaxial deposition of a silicon layer on a basic silicon substrate with (110) orientation at low pressure (40-120 Torr) and temperature (1000-1200°C) using trichlorosilane or dichlorosilane, which significantly reduces surface defects and maintains low surface roughness, effectively covering underlying defects without degrading the substrate's quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional crystal growth processes are used to manufacture (110) oriented silicon substrates, then the substrates can be produced, but the process is expensive and shows very low yield due to low crystal growth and high defect density
Solution Approach 1:
The patent changes the crystal orientation parameter from conventional (100) to (110) orientation, which fundamentally alters the crystal growth characteristics and defect formation behavior. This parameter change enables higher yield by reducing the density of crystal defects such as COPs and oxygen precipitations that plague conventional substrates
Solution Approach 2:
The patent uses (100) oriented silicon substrates as templates or copies to create the (110) oriented substrates through bonding and orientation transformation. This approach allows leveraging the well-established manufacturing processes for (100) substrates while achieving the benefits of (110) orientation, thereby reducing manufacturing costs and improving yield
2Manufacturing precision
If heat treatment is applied to (110) oriented silicon substrates, then surface reconstruction can be attempted, but the substrates become easily rough and develop surface defects due to low energy planes
Solution Approach 1:
The patent applies preliminary surface preparation and protective measures before heat treatment to prevent the formation of surface roughness and defects. By preparing the surface in advance and using appropriate processing conditions, the harmful effects of heat treatment on (110) oriented substrates are counteracted, maintaining high surface quality throughout the 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
This method results in (110) silicon substrates with virtually no surface defects, enhancing surface quality and enabling the production of high-performance hybrid substrates with low haze and high hole mobility, suitable for CMOS devices, while reducing production costs and time.
Implementation Method 1
depositing epitaxially a silicon layer with (110) orientation on the basic silicon substrate
Implementation Method 2
depositing epitaxially a silicon layer with (110) orientation on the basic silicon substrate at a pressure between about 40 Torr and about 120 Torr, preferably 80 Torr, and at a temperature between about 1000° C. and about 1200° C. and using trichlorosilane or dichlorosilane as silicon precursor gas
Data Source
AI summary
The present invention relates to method of fabricating a (110) oriented silicon substrate and to a method of fabricating a bonded pair of substrates comprising such a (110) oriented silicon substrate. The invention further relates to a silicon substrate with (110) orientation and to a bonded pair of silicon substrates comprising a first silicon substrate with (100) orientation and a second silicon substrate with (110) orientation. Methods include the steps of providing a basic silicon substrate with (110) orientation, the basic silicon substrate having a roughness being equal or less than 0.15 nm RMS, and depositing epitaxially a silicon layer with (110) orientation on the basic silicon substrate at a pressure between 40 Torr to 120 Torr, and at a temperature between about 1000° C. and about 1200° C. and using trichlorosilane or dichlorosilane as silicon precursor gas.