Shielded Well Structure for High-Voltage Leakage Suppression
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Solution Overview
Problem
High voltage semiconductor structures face challenges in managing high breakdown voltages and frequencies while preventing leakage currents and parasitic NPN bipolar transistor activation, especially in RF devices and ESD protection circuits.
Innovation Solution
A semiconductor structure design incorporating a semiconductor substrate with multiple well regions, a gate, shielding structures, and a bulk ring, where the shielding structures are positioned to overlap the well regions and gate, preventing voltage coupling and grounding to suppress leakage currents and enhance breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage signals are applied to semiconductor devices, then the devices can handle high breakdown voltages and high frequencies, but parasitic NPN bipolar transistors may be triggered causing leakage currents
Solution Approach 1:
A shielding structure made of conductive material (such as doped polysilicon or metal) is introduced as an intermediary element positioned between the high voltage signal path and the gate's P-type well region. This shielding structure captures and redirects high voltage signals before they can couple into the P-type well and trigger parasitic NPN bipolar transistors, thereby eliminating the harmful leakage currents while preserving the high voltage handling capability
2Object-generated harmful factors
If shielding structures are added to prevent high voltage signal coupling, then leakage currents are suppressed, but device complexity increases
Solution Approach 1:
The shielding structure is merged with existing device components during the fabrication process. The shielding structure is formed as part of the interlayer dielectric stack and is integrated with the gate structure and contact regions, allowing it to perform its shielding function without requiring separate fabrication steps or additional discrete components, thus minimizing the increase in device 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
The design effectively prevents leakage currents and increases breakdown voltage by grounding the shielding structures, thereby preventing parasitic NPN bipolar transistor activation and ensuring reliable operation in high voltage and RF applications.
Implementation Method 1
Incorporating shielding structures, such as polysilicon or metal plates, between the gate and bulk ring of semiconductor devices to prevent high voltage signals from coupling to the gate's P-type well regions
Implementation Method 2
grounding the shielding structures and preventing the activation of parasitic NPN bipolar transistors
Data Source
AI summary
A semiconductor structure is provided. At least one first well region is disposed in a semiconductor substrate and has a first conductivity type. At least one gate of a transistor is disposed over the first well region and extends in a first direction. At least one second well region and at least one third well region are disposed on opposite sides of the first well region and extend in the first direction. The second and third well regions have a second conductivity type. A first shielding structure is disposed on at least one end of the gate and partially overlaps the first well region in a vertical projection direction. The first shielding structure is separated from the end of the gate. A bulk ring is disposed in the semiconductor substrate and surrounds the gate, the second well region, the third well region, and the first shielding structure.