Vertical ESD Diode Structure With Stacked Junction Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor devices are susceptible to damage from electrostatic discharge (ESD) events, which can cause high voltage spikes leading to physical damage such as breakdown, metal electromigration, and gate oxide rupture, highlighting the need for effective ESD protection circuits.
Innovation Solution
The development of an ESD protection diode structure featuring a P-type and N-type epitaxy region configuration with a junction region, where the ESD current path is directed through alternating semiconductor layers, providing a current discharge path to mitigate ESD effects without requiring bulk transistors, and eliminating traditional well regions to suit backside IC structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ESD protection circuits are used, then ESD protection is provided, but device complexity and parasitic capacitance increase
Solution Approach 1:
The ESD protection function is segmented into multiple thin semiconductor layers (e.g., alternating n-type and p-type layers) stacked between the first and second epitaxy regions. This segmentation allows the ESD current to be dissipated across multiple junctions, providing effective protection while maintaining a compact structure without requiring complex bulk transistor circuits.
Solution Approach 2:
The invention transitions from planar ESD protection structures to a vertical stacked configuration with multiple semiconductor layers arranged in the thickness direction. This dimensional change enables efficient ESD current paths through the vertical stack, reducing the lateral footprint and parasitic capacitance while maintaining protection effectiveness.
2Reliability
If bulk transistors are used for ESD protection, then ESD current can be discharged, but device area and complexity increase
Solution Approach 1:
The ESD protection mechanism is moved from lateral bulk transistor structures to a vertical stacked configuration. Multiple thin semiconductor layers are stacked in the thickness direction between contact regions, enabling ESD current discharge paths that occupy minimal lateral area while providing robust protection capability.
Solution Approach 2:
Instead of using a single large bulk transistor, the invention uses multiple thin semiconductor layers that replicate the ESD protection function in a compact vertical stack. Each layer contributes to the overall ESD current handling capability, providing equivalent or superior protection with reduced area.
3Reliability
If traditional well regions are included, then ESD protection is achieved, but compatibility with backside IC structures is reduced
Solution Approach 1:
The invention extracts and eliminates the traditional well region structure from the ESD protection design. Instead of relying on p-well or n-well regions formed in bulk substrate, the protection function is achieved through alternating n-type and p-type semiconductor layers stacked between contact regions, making the structure compatible with backside IC configurations where well regions cannot be formed.
Solution Approach 2:
The invention changes the structural parameters of the ESD protection mechanism from bulk-based well regions to thin-film stacked layers. This parameter change in the vertical dimension enables the same ESD protection function to be achieved without requiring lateral well region formation, thus compatible with backside IC structures.
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 configuration effectively reduces semiconductor failures by providing a robust ESD protection mechanism, enhancing the reliability of electronic devices by directing ESD current efficiently and minimizing parasitic capacitance, thus preventing damage from ESD events.
Implementation Method 1
ESD stress events may cause voltage in excess of the kilovolts range to be coupled to a pin of an integrated circuit (IC). Without ESD protection, the internal devices can be damaged or destroyed.
Implementation Method 2
a junction region over the semiconductor substrate and between the first and second epitaxy regions, wherein the junction region comprises a plurality of Si layers and a plurality of SiGe layers alternatingly stacked
Data Source
AI summary
Electrostatic discharge (ESD) structures are provided. An ESD structure includes a semiconductor substrate, a first epitaxy region with a first type of conductivity over the semiconductor substrate, a second epitaxy region with a second type of conductivity over the semiconductor substrate, and a plurality of first semiconductor layers and a plurality of second semiconductor layers. The first and second semiconductor layers are alternatingly stacked over the semiconductor substrate and between the first and second epitaxy regions. A first conductive feature is formed over the first epitaxy region and outside an oxide diffusion region. A second conductive feature is formed over the second epitaxy region and outside the oxide diffusion region. The oxide diffusion region is disposed between the first and second conductive features.