FDSOI Integrated Circuit ESD Protection Using Partial Isolation Trenches
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated circuits produced using FDSOI technology face challenges in achieving distinct threshold voltages for transistors while maintaining low power consumption and high switching speed, and require effective protection against electrostatic discharges without compromising integration density.
Innovation Solution
The integration of buried insulating layers, ground planes, and wells with opposite doping types, along with bias electrodes and shallow isolation trenches, enables the creation of ESD protection devices that are not detrimental to integration density and provide localized protection against electrostatic discharges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If isolation trenches are extended as far as the wells to electrically insulate transistors, then transistor isolation is improved, but integration density deteriorates
Solution Approach 1:
The isolation trenches are implemented with partial depth extension - they isolate the electronic components laterally but stop before reaching the wells vertically. This partial isolation action is sufficient to prevent lateral parasitic triggering while preserving vertical electrical connections to the wells, thus maintaining both transistor isolation and integration density
2Adaptability or versatility
If different gate materials are integrated to produce transistors with distinct threshold voltages, then threshold voltage differentiation is improved, but manufacturing complexity and cost deteriorate
Solution Approach 1:
Instead of changing gate materials, the patent differentiates transistor threshold voltages by modifying structural parameters - specifically using different thicknesses of the buried insulating layer and adjusting the doping levels in the wells. This parameter-based approach achieves the same functional differentiation as material changes would provide, but with simpler manufacturing processes
3Use of energy by moving object
If FDSOI technology is used to reduce static consumption and improve switching speed, then power efficiency is improved, but protection against electrostatic discharges deteriorates
Solution Approach 1:
The patent introduces an intermediary protection structure - a laterally extending isolation trench system that acts as a barrier between electrostatic discharge sources and the sensitive FDSOI transistors. This intermediary structure provides ESD protection without interfering with the low-power operation of the FDSOI devices, as it works passively to divert or block discharge paths
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 solution allows for efficient modulation of threshold voltages and effective protection against electrostatic discharges, ensuring reliable operation and maintaining high integration density, while reducing sensitivity to accidental triggering and ionizing radiation.
Implementation Method 1
separating a slender silicon layer (a few nanometers) on a silicon substrate by a relatively thick layer of insulant
Implementation Method 2
the first well exhibiting a first type of doping, the second well exhibiting a second type of doping opposite to the first type of doping
Data Source
AI summary
An integrated circuit includes an UTBOX insulating layer under and plumb with first and second electronic components, and corresponding ground planes and oppositely-doped wells made plumb with them. The wells contact with corresponding ground planes. A pair of oppositely doped bias electrodes, suitable for connecting corresponding bias voltages, contacts respective wells and ground planes. A third electrode contacts the first well. A first trench isolates one bias electrode from the third electrode and extends through the layer and into the first well. A second trench isolates the first bias electrode from one component. This trench has an extent that falls short of reaching an interface between the first ground plane and the first well.