Deep Trench Isolation Structure for Semiconductor Latch-Up Immunity
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Solution Overview
Problem
Conventional semiconductor devices suffer from latch-up conditions due to parasitic device activation, leading to excessive current flow and potential destruction, with the low-impedance path persisting even after the trigger is removed.
Innovation Solution
A semiconductor structure incorporating a buried P+ semiconductor layer connected to a deep trench isolation structure, combined with a P− epitaxial semiconductor layer, which reduces parasitic NPN gain and enhances latch-up immunity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor device structure is used, then device simplicity is maintained, but latch-up immunity deteriorates due to parasitic device activation
Solution Approach 1:
The device structure is segmented into distinct regions including a first semiconductor region with a first layer and second layer, a second semiconductor region with first and second layers, and a third semiconductor region. This segmentation isolates parasitic devices in different regions, preventing their activation and improving latch-up immunity while maintaining manageable structural complexity.
Solution Approach 2:
Different regions of the semiconductor device are assigned different conductivity types and dopant concentrations tailored to local requirements. The first semiconductor region has specific doping characteristics, the second region has opposite conductivity type, and the third region provides additional isolation. This local optimization enhances latch-up immunity without requiring complete structural redesign.
2Reliability
If deep trench isolation structure extending through multiple semiconductor layers is implemented, then parasitic NPN gain is reduced and latch-up immunity is enhanced, but manufacturing complexity increases
Solution Approach 1:
The deep trench isolation structure extends vertically through multiple semiconductor layers (first, second, and third layers) rather than only at the surface. This three-dimensional isolation approach effectively separates parasitic NPN devices from activation paths, reducing parasitic gain and enhancing latch-up immunity. The vertical extension through multiple layers provides comprehensive isolation while the trench geometry allows for systematic manufacturing processes.
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to a device with improved latch-up immunity and methods of manufacture. The structure includes: a semiconductor substrate including a layer of a first conductivity type; a first semiconductor material over the layer of the first conductivity type, the first semiconductor layer including the first conductivity type and a layer of a second conductivity type; a second semiconductor material of the second conductivity type over the layer of the second conductivity type; and a deep trench isolation structure electrically connecting to the layer of the first conductivity type, the deep trench isolation layer extending through the first semiconductor material and the second semiconductor material.