Alternating Doped Wafer Layout for RF Chip Leakage Control
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Solution Overview
Problem
The diffusion of elements from the epitaxial layer into the semiconductor substrate leads to insufficient semiconductor resistance, affecting the performance of RF chips.
Innovation Solution
A semiconductor wafer with alternately arranged first and second doped regions, where the first doped regions are formed through a combination of ion implantation processes and a barrier layer, and the second doped regions are created by diffusing N-type dopants from a doping material layer, ensuring a controlled doping concentration to restrict electron movement and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If elements are diffused from the epitaxial layer into the semiconductor substrate, then the doping concentration in the substrate increases, but the semiconductor resistance becomes insufficient
Solution Approach 1:
The semiconductor substrate is divided into multiple alternately arranged first doped regions and second doped regions with different doping concentrations. This segmentation allows different regions to serve different functions: high-doping regions provide sufficient resistance while low-doping regions maintain appropriate conductivity, resolving the contradiction between needing high doping concentration and maintaining sufficient resistance.
Solution Approach 2:
Different regions of the semiconductor substrate are given different local doping concentrations through the alternating first and second doped regions. The first doped regions have higher doping concentration to provide resistance, while the second doped regions have lower doping concentration to maintain conductivity. This local quality variation allows the substrate to simultaneously achieve both high resistance where needed and appropriate conductivity where needed.
2Reliability
If a barrier layer is used to prevent element diffusion, then the semiconductor resistance is maintained, but the manufacturing process complexity increases
Solution Approach 1:
The first and second doped regions are formed in advance during the substrate preparation stage, before the epitaxial layer is grown. By pre-establishing the alternating doped region structure with appropriate doping concentrations, the patent prevents element diffusion issues before they occur during epitaxial growth, eliminating the need for additional barrier layers and simplifying the overall manufacturing process.
3Reliability
If the doping concentration is uniformly increased throughout the substrate, then the resistance value improves, but the electron movement restriction becomes excessive and affects device performance
Solution Approach 1:
Instead of uniformly increasing doping concentration throughout the substrate, the patent applies high doping concentration only to the first doped regions where resistance is needed, while maintaining lower doping concentration in the second doped regions where electron movement is required. This local quality differentiation resolves the contradiction between improving resistance value and maintaining appropriate electron mobility for device operation.
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 improves the resistance value of the semiconductor substrate, reducing the risk of current leakage and enhancing the stability and quality of RF chips by alternately arranging doped regions with varying doping concentrations.
Implementation Method 1
performing a first ion implantation process on a first surface of the semiconductor substrate to form an N-type lightly doped region in the semiconductor substrate
Implementation Method 2
heating the N-type doping material layer to drive N-type dopants in the N-type doping material layer diffusing into the semiconductor substrate, wherein: part of the N-type dopants diffuse into the semiconductor substrate from the N-type doping material layer after passing through the barrier layer
Data Source
AI summary
A wafer includes a semiconductor substrate. The semiconductor substrate includes a plurality of first doped regions and a plurality of second doped regions. The first doped regions and the second doped regions are located on a first surface of the semiconductor substrate. The second doped regions contact the first doped regions. The first doped regions and the second doped regions are alternately arranged. Both of the first doped regions and the second doped regions include a plurality of N-type dopants. The doping concentration of the N-type dopants in each of the first doped regions is not greater than the doping concentration of the N-type dopants in each of the second doped regions.