Substrate Isolation Structure for Low-Leakage Semiconductor Active Regions
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Solution Overview
Problem
As semiconductor devices become more integrated and transistors smaller, leakage currents increase, necessitating the development of substrates with a silicon-on-insulator (SOI) structure to reduce these currents.
Innovation Solution
A semiconductor device is designed with a substrate insulating structure that includes lower insulating layers, first and second sidewall insulating layers, and a gate structure with a gate dielectric layer and gate electrode, which reduces leakage currents by defining an active region and improving current drivability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transistor size is reduced to increase degree of integration, then productivity and device functionality are improved, but leakage currents increase
Solution Approach 1:
The substrate insulating structure is divided into multiple segments: lower insulating layer, first sidewall insulating layers, and second sidewall insulating layers. This segmented approach creates comprehensive isolation of the active region from the substrate, effectively blocking leakage current paths while allowing continued miniaturization of transistors to increase integration density.
Solution Approach 2:
The patent applies insulating properties locally at the substrate-active region interface through the substrate insulating structure. By concentrating insulation where leakage occurs (at the substrate boundary) rather than throughout the entire device, the solution reduces leakage currents in critical areas while maintaining transistor performance and enabling higher integration.
2Object-generated harmful factors
If substrate insulating structure is added to reduce leakage currents, then leakage currents are reduced, but device complexity increases
Solution Approach 1:
Multiple insulating layers (lower insulating layer, first sidewall insulating layers, second sidewall insulating layers) are merged into a single integrated substrate insulating structure. This unified structure performs multiple isolation functions simultaneously, reducing leakage currents effectively while presenting a cohesive architectural element rather than separate complex components.
Solution Approach 2:
The substrate insulating structure serves multiple functions: isolating the active region from the substrate to reduce leakage currents, defining the active region boundaries, and providing mechanical support. This multi-functionality reduces the need for additional separate structures, thereby managing complexity while achieving leakage reduction.
3Reliability
If active region is defined by substrate insulating structure, then current drivability and performance are improved, but manufacturing precision requirements increase
Solution Approach 1:
The substrate insulating structure is formed in advance before the active region and transistor components are created. This preliminary definition of the insulating boundaries provides a pre-established template that guides subsequent manufacturing steps, ensuring consistent active region formation and reducing precision requirements during later processing stages.
Solution Approach 2:
The substrate insulating structure acts as an intermediary element between the substrate and the active region. It mediates the interface relationship, providing a well-defined boundary that simplifies the manufacturing process by serving as a reference structure for forming the active region, thereby reducing the precision demands on direct substrate-to-active-region alignment.
Data Source
AI summary
A semiconductor device includes a substrate having a recess therein that is partially filled with at least two semiconductor active regions. The recess has sidewalls and a bottom that are sufficiently lined with corresponding substrate insulating layers that the at least two semiconductor active regions are electrically isolated from the substrate, which surrounds the sidewalls and bottom of the recess. A sidewall insulating layer is provided, which extends as a partition between first and second ones of the at least two semiconductor active regions, such that the first and second ones of the at least two semiconductor active regions are electrically isolated from each other. First and second gate electrodes are provided in the first and second active regions, respectively.