N-Doped SiC Deposition with Complementary Gas Inlet Profiles
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Solution Overview
Problem
The existing methods for depositing n-doped SiC layers in CVD reactors face challenges in achieving homogeneous dopant distribution due to non-linear depletion curves of reactive gases, leading to inhomogeneous dopant incorporation, particularly at the edge of the substrate.
Innovation Solution
The method involves dividing the process gas flow into vertically stacked gas inlet zones and selecting dopant carriers to generate complementary doping profiles, such as NH₃ and N₂, to compensate for edge enhancements and reductions, ensuring a homogeneous dopant distribution by adjusting mass flows and gas inlet zone positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional MBE or sputtering methods are used to deposit n-doped SiC, then the doping process becomes complex and costly, but the doping efficiency and uniformity deteriorate due to contamination and process complexity
Solution Approach 1:
The patent combines the doping source and SiC material source into a single composite target. This merging eliminates the need for separate doping processes (MBE or sputtering), simplifying manufacturing while ensuring uniform doping through simultaneous deposition of SiC and dopants from the same target surface.
Solution Approach 2:
The patent introduces a composite target as an intermediary that contains both SiC material and doping elements in specific layers. This intermediary structure enables controlled dopant release during sputtering, achieving uniform doping without complex multi-step processes or contamination from separate doping operations.
2Reliability
If separate doping processes (MBE or sputtering) are used after SiC deposition, then doping control becomes difficult and contamination occurs, but the process steps increase leading to higher costs
Solution Approach 1:
The patent performs preliminary action by pre-structuring the doping elements within the composite target before deposition. The doping elements are arranged in specific layers or regions in the composite target, enabling controlled dopant release during sputtering and eliminating the need for subsequent separate doping processes.
Solution Approach 2:
The patent merges material deposition and doping into a single simultaneous process using the composite target. This combining eliminates multiple process steps (separate SiC deposition followed by separate doping), reducing device complexity and preventing contamination that occurs with sequential processes.
3Productivity
If conventional sputtering with separate doping is used, then the production time increases, but the doping efficiency decreases due to contamination and process complexity
Solution Approach 1:
The patent enables continuous useful action by performing both SiC material deposition and doping in a single uninterrupted sputtering process using the composite target. This eliminates idle time between separate processes and maintains continuous dopant incorporation, improving both productivity and doping efficiency.
Solution Approach 2:
The patent combines material deposition and doping into one simultaneous process step using the composite target. This merging eliminates the time required for separate doping operations and prevents contamination that reduces doping efficiency, thereby improving overall productivity.
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 a nearly uniform dopant distribution across the SiC layer, minimizing concentration variations and enhancing the homogeneity of the deposited layer.
Implementation Method 1
a sputtering method in which a composite target including a SiC target and a doping element target is used
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The invention relates to a method for depositing an SiC layer, wherein an NH3-containing first doping gas flow (D1), a second N2-containing doping gas flow (D2), a C2H4-containing first growth gas flow (Q1) and an HCl3Si-containing second growth gas flow (Q2) flow in a horizontal direction over a heated substrate. The two doping gas flows (D1, D2) are fed, in a manner controlled separately from one another, into a process chamber (2) through gas inlet zones (4, 5, 6) arranged vertically one above the other. The mass flows of the doping gas flows (D1, D2) or the vertical position of the gas inlet zones (4, 5, 6) through which the two doping gas flows (D1, D2) flow are selected such that they generate first and second doping profiles (a, b) which are oppositely curved in relation to one another such that by way of a beneficial selection of the ratio of the doping gas flows (D1, D2), a homogeneous dopant profile can be achieved in the deposited layer.