Lateral High-Voltage Diode Integration with Isolation
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Solution Overview
Problem
There is a need to integrate high-voltage devices, such as high-voltage field effect transistors, diodes, and thyristors, with low-voltage circuitry on a single semiconductor wafer using low-voltage foundry technology, while ensuring the high-voltage devices can withstand operating voltages greater than 20 volts without damaging the low-voltage devices.
Innovation Solution
The integration of lateral high-voltage devices, like lateral high-voltage diodes and thyristors, is achieved using a Silicon-on-Insulator (SOI) wafer or a traditional semiconductor wafer with an insulator layer for vertical isolation, and deep trench isolation for lateral isolation, incorporating intrinsic materials to enhance breakdown voltage capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-voltage devices are integrated with low-voltage circuitry on a single semiconductor wafer, then device density and integration are improved, but the risk of voltage damage to low-voltage devices increases
Solution Approach 1:
The semiconductor wafer is divided into distinct high-voltage and low-voltage regions separated by isolation structures. Deep trench isolation physically segments the wafer into isolated zones, allowing high-voltage devices and low-voltage circuitry to coexist without electrical interference or damage risk.
Solution Approach 2:
Insulator layers and deep trench isolation structures serve as intermediary barriers between high-voltage and low-voltage regions. These intermediary structures block voltage propagation and prevent high-voltage spikes from damaging sensitive low-voltage components while maintaining physical proximity for integration.
2Reliability
If isolation structures are added to protect low-voltage devices from high-voltage damage, then device reliability is improved, but manufacturing complexity increases
Solution Approach 1:
Multiple isolation functions are merged into a single integrated isolation structure. The deep trench isolation simultaneously provides electrical isolation, mechanical support, and stress management, reducing the need for separate isolation components and simplifying the overall device architecture.
Solution Approach 2:
The isolation structures utilize controlled material properties and geometric parameters to achieve protection. By adjusting trench depth, insulator layer thickness, and material composition, effective protection is achieved while optimizing manufacturing processes and minimizing structural complexity.
3Strength
If intrinsic material is used between anode and cathode to increase breakdown voltage, then high-voltage capability is improved, but device fabrication complexity increases
Solution Approach 1:
Intrinsic material is selectively applied only in specific regions where high breakdown voltage is required, such as between anode and cathode regions. This localized approach enhances high-voltage capability where needed while maintaining simpler structures in low-voltage areas, reducing overall fabrication complexity.
Solution Approach 2:
The intrinsic material layer is incorporated during the preliminary stages of device fabrication, before subsequent processing steps. By establishing the high-voltage barrier early in the manufacturing process, later fabrication steps are simplified and overall process complexity is reduced.
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 allows for the successful integration of high-voltage devices with low-voltage circuitry on a single semiconductor die, enabling the creation of high-voltage circuits that can handle voltages exceeding 20 volts without damaging the low-voltage components, thus addressing the challenge of combining high and low-voltage technologies on a single wafer.
Implementation Method 1
The lateral high-voltage devices may be vertically isolated from the low-voltage devices or other high-voltage devices by an insulator layer
Implementation Method 2
The reverse breakdown voltage capability of the LHVD may be increased by using an intrinsic material between the anode and the cathode
Implementation Method 3
in a lateral high voltage thyristor, such as a lateral high-voltage Silicon-controlled rectifier (LHV-SCR), the withstand voltage capability of the LHV-SCR may be increased by using an intrinsic material between the anode and the cathode
Implementation Method 4
The lateral high-voltage devices may be laterally isolated from the low-voltage devices or other high-voltage devices using deep trench isolation
Data Source
AI summary
The present invention relates to integration of lateral high-voltage devices, such as a lateral high-voltage diode (LHVD) or a lateral high-voltage thyristor, with other circuitry on a semiconductor wafer, which may be fabricated using low-voltage foundry technology, such as a low-voltage complementary metal oxide semiconductor (LV-CMOS) process. The other circuitry may include low-voltage devices, such as switching transistors used in logic circuits, computer circuitry, or the like, or other high-voltage devices, such as a microelectromechanical system (MEMS) switch. The reverse breakdown voltage capability of the LHVD may be increased by using an intrinsic material between the anode and the cathode. Similarly, in a lateral high-voltage thyristor, such as a lateral high-voltage Silicon-controlled rectifier (LHV-SCR), the withstand voltage capability of the LHV-SCR may be increased by using an intrinsic material between the anode and the cathode.