Semiconductor Structure With Conductive Plug Through Isolation
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Solution Overview
Problem
Current semiconductor devices, such as LDMOS and EDMOS, face limitations in reducing on-resistance (Ron) despite various structural modifications, with only about 5% improvement in the Ron to breakdown voltage ratio achieved through well schemes or implant optimization.
Innovation Solution
A semiconductor structure is designed with a conductive plug penetrating into the isolation as the drain side, featuring a substrate with deep and first/second wells of opposing conductive types, a gate electrode between the wells, and an isolation with a conductive plug connecting a doping electrode region, which reduces on-resistance by creating a shorter current path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional well schemes or implant optimization are used, then device structure is maintained, but on-resistance reduction is limited to about 5% improvement
Solution Approach 1:
The patent introduces a conductive plug extending vertically through the isolation layer to connect with the deep well, creating a three-dimensional current path. This vertical dimension bypasses the high-resistance isolation region, reducing on-resistance by more than 10% without complicating the planar device layout.
Solution Approach 2:
The conductive plug acts as an intermediary element that bridges the connection between the deep well and the surface contact, providing a low-resistance current path through the isolation layer. This mediator enables current flow without requiring modification of the isolation material itself.
2Manufacturing precision
If isolation depth is increased to reduce on-resistance, then current path is shortened, but manufacturing complexity increases
Solution Approach 1:
The isolation layer is formed to a predetermined depth before the conductive plug is introduced. This preliminary formation establishes a defined interface and simplifies subsequent plug formation, as the plug only needs to penetrate to the existing isolation depth rather than requiring coordinated formation of both structures.
Solution Approach 2:
The device structure is segmented into distinct functional regions: the isolation layer forming an electrical boundary, the deep well providing the substrate connection, and the conductive plug creating the vertical current path. This segmentation allows each component to be optimized and manufactured independently using standard processes.
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 semiconductor structure effectively decreases on-resistance by more than 10%, enhancing the electrical characteristics and competitiveness of high-power devices, particularly in PMIC applications, while being compatible with existing manufacturing processes for mass production.
Implementation Method 1
a conductive plug penetrating into the isolation and reaching a bottom of the isolation... the conductive plug connects the first doping electrode region
Data Source
AI summary
A semiconductor structure comprises a substrate having a first conductive type; a deep well having a second conductive type formed in the substrate and extending down from a surface of the substrate; a first well having the first conductive type and a second well having the second conductive type both formed in the deep well and extending down from the surface of the substrate, and the second well spaced apart from the first well; a gate electrode formed on the substrate and disposed between the first and second wells; an isolation extending down from the surface of the substrate and disposed between the gate electrode and the second well; a conductive plug penetrating into the isolation and reaching the bottom thereof; and a first doping electrode region having the second conductive type, formed within the second well and below the isolation to connect the conductive plug.