Diode Doping Profile for ESD Protection
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Solution Overview
Problem
Existing transient voltage suppression designs are insufficient for supporting current and future automotive high-speed signal interface voltage requirements, particularly exhibiting unacceptably large variations in breakdown voltage, which is a concern for electrostatic discharge (ESD) protection in electronic devices.
Innovation Solution
The development of an electronic device with a diode structure that includes a substrate, semiconductor layers, and doped regions, where the doping concentration profiles are carefully controlled to reduce variations in breakdown voltage, ensuring a lower average breakdown voltage while exceeding minimum triggering voltages, and incorporating a zener diode configuration for effective ESD protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior transient voltage suppression designs are used, then ESD protection is provided, but breakdown voltage varies unacceptably
Solution Approach 1:
The patent applies parameter changes by precisely controlling doping concentrations and layer thicknesses in the semiconductor structure. Specifically, the n-type doping concentration is maintained between 1×10^16 to 1×10^18 atoms/cm³, and the p-type doping concentration between 1×10^18 to 1×10^20 atoms/cm³, with layer thicknesses controlled within specific ranges. These parameter optimizations reduce breakdown voltage variation while maintaining reliable ESD protection across different production runs.
Solution Approach 2:
The patent employs a composite semiconductor structure consisting of multiple layers with different doping types and concentrations. The structure includes an n-type semiconductor layer, a p-type semiconductor layer, and an n-type doped region, forming a complex pn junction diode. This composite material approach allows independent optimization of each layer's properties to achieve consistent breakdown voltage characteristics.
2Reliability
If ESD protection devices are attached to signal lines, then ESD protection is provided, but signal integrity may be interfered with due to capacitance
Solution Approach 1:
The patent uses thin semiconductor layers to create the ESD protection structure. The n-type semiconductor layer has a thickness of 0.5-5.0 micrometers, and the p-type semiconductor layer has a thickness of 0.5-3.0 micrometers. These thin film structures provide effective ESD protection while minimizing the capacitance added to signal lines, thereby preserving signal integrity.
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 results in a diode with reduced variation in breakdown voltage, enabling effective ESD protection across a range of voltage conditions, ensuring reliable operation even when process steps are at the edges of production specifications, and providing consistent performance across different production runs.
Implementation Method 1
a first doped region at an interface of and extending into the first and second semiconductor layers, wherein the first doped region has a third dopant with a second conductivity type opposite the first conductivity type
Implementation Method 2
a first diode is formed at a pn junction where a second dopant concentration profile of the first doped region intersects the relatively flatter portion of the first dopant concentration profile
Implementation Method 3
incorporating a zener diode configuration for effective ESD protection
Implementation Method 4
ESD protection across a range of voltage conditions
Data Source
AI summary
An electronic device can include a substrate, lower and upper semiconductor layers over the substrate, and a doped region at the interface between the lower and upper semiconductor layers. The doped region can have a conductivity type opposite that of a dopant within the lower semiconductor layer. Within the lower semiconductor layer, the dopant can have a dopant concentration profile that has a relatively steeper portion adjacent to the substrate, another relatively steeper portion adjacent to an interface between the first and second semiconductor layers, and a relatively flatter portion between the relative steeper portions. A diode lies at a pn junction where a second dopant concentration profile of the first doped region intersects the relatively flatter portion of the first dopant concentration profile. The electronic device can be formed using different processes described herein.