Integrated Circuit Transistors with Graded Doping for Mixed Voltage Integration
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Solution Overview
Problem
The integration of function circuit modules with different operating voltage ranges into a single semiconductor chip is challenging due to complex device configurations, leading to increased fabrication costs and unsatisfactory production yields.
Innovation Solution
An integrated circuit device is designed with two transistors having distinct operating voltages, featuring specific structures such as high-voltage well regions, heavily doped regions, and multilayered isolation structures, allowing for the coexistence of transistors with operating voltages up to 800V and 5V/30V on the same chip without increasing the number of photo masks or ion implantation steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If function circuit modules with different operating voltage ranges are integrated into the same semiconductor chip, then the functionality and versatility of the chip is improved, but the device complexity and fabrication difficulty increase
Solution Approach 1:
The patent applies local quality by creating different doping concentration regions within the semiconductor substrate. Specifically, it forms a first doping concentration region with a first doping concentration and a second doping concentration region with a second doping concentration, where the doping concentrations differ to support different operating voltages. This allows high-voltage and low-voltage circuit modules to coexist on the same chip by providing locally optimized electrical characteristics for each voltage requirement.
Solution Approach 2:
The patent segments the semiconductor substrate into distinct functional regions with different electrical properties. By dividing the substrate into multiple doping concentration regions and forming isolation structures between them, the patent enables independent optimization of each region for specific voltage requirements while maintaining overall chip integration.
2Adaptability or versatility
If complex device configurations are used to integrate different function circuit modules, then the operating voltage ranges are accommodated, but the fabrication cost increases
Solution Approach 1:
The patent merges multiple functionality into a unified semiconductor structure by integrating high-voltage and low-voltage circuit modules on the same substrate using a common fabrication process. The isolation structure and doping regions are formed in an integrated manner, combining what would traditionally require separate processing into a single streamlined workflow, thereby reducing fabrication cost.
Solution Approach 2:
The patent creates a universal semiconductor substrate structure that can accommodate multiple operating voltage ranges simultaneously. The doping concentration regions and isolation structures are designed to serve dual purposes: supporting both high-voltage and low-voltage operations while maintaining compatibility with standard fabrication processes, thus achieving multi-functionality without proportionally increasing complexity.
3Adaptability or versatility
If complex device configurations are used to integrate different function circuit modules, then the voltage requirements are met, but the production yield decreases
Solution Approach 1:
The patent performs preliminary actions by pre-forming the doping concentration regions and isolation structures during the early stages of fabrication. The first and second doping concentration regions are created before final device assembly, and the isolation structure is formed in advance to define the boundaries between high-voltage and low-voltage regions. This preliminary structuring simplifies subsequent processing steps and reduces the likelihood of defects.
Solution Approach 2:
The patent utilizes parameter changes by varying the doping concentration across different regions of the substrate. By controlling the doping concentration parameter (first doping concentration vs. second doping concentration), the patent optimizes the electrical characteristics for different voltage requirements while maintaining a consistent fabrication process, thereby improving production yield through parameter optimization rather than process complexity.
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 solution enables the simultaneous construction of transistors with varying operating voltages on a single semiconductor chip, reducing fabrication complexity and costs while improving production yield.
Implementation Method 1
The first source structure includes a high voltage first-polarity well region, a first-polarity body region, a heavily doped first-polarity region, a second-polarity grade region and a heavily doped second-polarity region
Implementation Method 2
The dopant concentrations of the high voltage first-polarity well region, the first-polarity body region, the heavily doped first-polarity region, the second-polarity grade region and the heavily doped second-polarity region of the first transistor are in the following scale level 1013 cm−2, 1013 cm−2, 1015 cm−2, 1013 cm−2 and 1015 cm−2, respectively
Implementation Method 3
The isolation structure is a multilayered structure including a field oxide layer and a silicon oxide layer, wherein the thickness of the silicon oxide layer is about 5000 angstroms
Implementation Method 4
the silicon oxide layer is formed by carrying out a low-pressure tetraethylorthosilicate chemical vapor deposition process
Implementation Method 5
The first gate structure includes a gate dielectric layer and a segmented gate structure. The gate dielectric layer is arranged between the first drain structure and the first source structure
Data Source
AI summary
An integrated circuit device includes a semiconductor substrate and a first transistor and a second transistor constructed in the semiconductor substrate. The first transistor has a first operating voltage higher than a second operating voltage of a second transistor. The first transistor includes a first drain structure, a first source structure, an isolation structure and a first gate structure. The first source structure includes a high voltage first-polarity well region, a first-polarity body region, a heavily doped first-polarity region, a second-polarity grade region and a heavily doped second-polarity region. The heavily doped second-polarity region is surrounded by the second-polarity grade region. The second-polarity grade region is surrounded by the first-polarity body region. The second transistor includes a second drain structure, a second source structure, a second gate structure and a first-polarity drift region. The first-polarity drift region and the first-polarity body region have the same dopant concentration.