Semiconductor Structure With Segmented Isolation Trenches
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Solution Overview
Problem
Semiconductor technology faces challenges in effectively isolating different types of transistors on the same semiconductor substrate, such as higher voltage and lower voltage transistors, which affects the integration and performance of integrated circuits.
Innovation Solution
The solution involves a semiconductor structure with advanced doping and isolation techniques, including the use of silicon nitride and oxide layers, thermal oxidation, and anisotropic etching to form trenches and dielectric structures that provide effective electrical isolation between transistors, allowing for the integration of higher voltage and lower voltage devices on the same substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If higher voltage and lower voltage transistors are integrated on the same semiconductor substrate, then device functionality and circuit complexity are improved, but electrical isolation between devices becomes more difficult to achieve
Solution Approach 1:
The patent divides the semiconductor substrate into distinct regions separated by isolation trenches. These trenches physically segment the substrate to prevent electrical interaction between higher voltage and lower voltage transistors, allowing both device types to coexist on the same substrate while maintaining proper electrical isolation.
Solution Approach 2:
The patent applies different dielectric materials and doping concentrations to different regions of the substrate. Specifically, higher voltage isolation regions use different material properties compared to lower voltage regions, optimizing each region's electrical characteristics for its specific voltage requirements while maintaining overall integration.
2Reliability
If isolation structures are added to separate different voltage transistors, then electrical isolation is improved, but device complexity and manufacturing steps increase
Solution Approach 1:
The isolation trenches serve multiple functions simultaneously: they provide electrical isolation between devices, define device boundaries, and can be filled with materials that also serve as etch stops or stress management layers. This multi-functionality reduces the need for separate dedicated isolation structures.
Solution Approach 2:
The patent implements a hierarchical isolation structure where shallow trenches and deep trenches are nested within each other. The shallow isolation trenches are formed first, then deeper trenches are etched and filled to provide additional isolation levels. This nested approach achieves comprehensive isolation while organizing the manufacturing process into manageable stages.
3Reliability
If deeper isolation trenches are formed to improve isolation, then electrical isolation between high voltage and low voltage devices is improved, but manufacturing precision and process difficulty increase
Solution Approach 1:
The isolation structure is segmented into multiple depth levels with different trench depths. Shallow trenches provide isolation for lower voltage devices while deeper trenches provide isolation for higher voltage devices. This segmentation allows each trench to be optimized for its specific isolation requirements rather than requiring all trenches to achieve maximum depth.
Solution Approach 2:
The patent forms shallow isolation trenches and fills them with dielectric material before forming the deeper isolation trenches. This preliminary action establishes a foundation that simplifies subsequent deep trench formation, as the shallow structures serve as guides and partial isolation barriers that reduce the burden on the deeper trenches.
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 enables efficient electrical isolation, reduces parasitic capacitance, and enhances the frequency of operation of semiconductor devices by allowing for the integration of both high voltage and low voltage transistors on the same substrate, improving the overall performance and complexity of integrated circuits.
Implementation Method 1
thermal oxidation
Implementation Method 2
anisotropic etching
Data Source
AI summary
In various embodiments, semiconductor structures and methods to manufacture these structures are disclosed. In one embodiment, a method includes forming a portion of the unidirectional transistor and a portion of a bidirectional transistor in or over a semiconductor material simultaneously. Other embodiments are described and claimed.