ESD Protection Device With Segmented Base Doping
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Solution Overview
Problem
Conventional ESD protection devices face challenges in achieving high response speed due to increased parasitic capacitance, which is exacerbated by induced doped regions in open-base bipolar transistors, affecting the reliability and service life of integrated circuit chips.
Innovation Solution
The ESD protection device incorporates an additional doped layer and extension ring to reduce junction capacitance, formed by specific doping concentrations and epitaxial growth methods, which invert induced doped regions and create depleted extension regions, thereby improving response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the doping concentration and junction area of the base-collector junction are increased to obtain low application voltages, then the electrostatic discharge capability is improved, but the parasitic capacitance CZ is greatly increased
Solution Approach 1:
The base region is segmented into multiple zones with different doping concentrations. The collector-base junction is divided into a first junction area with higher doping concentration for electrostatic discharge capability and a second junction area with lower doping concentration for reduced parasitic capacitance. This segmentation allows the device to achieve both high electrostatic discharge capability and fast response speed simultaneously.
2Speed
If the parasitic capacitance is reduced to improve response speed, then the response speed is improved, but the electrostatic discharge capability may be compromised
Solution Approach 1:
Different regions of the base-collector junction are assigned different doping concentrations to optimize local functions. The first junction area has higher doping concentration to provide low breakdown voltage and high electrostatic discharge capability, while the second junction area has lower doping concentration to minimize parasitic capacitance and improve response speed. This local quality differentiation resolves the contradiction between the two performance requirements.
3Ease of manufacture
If an induced doped region is introduced in the open-base bipolar transistor during conventional manufacturing, then the manufacturing process is simplified, but the equivalent capacitance C2 is increased
Solution Approach 1:
The harmful induced doped region that increases capacitance is removed or avoided in the critical base region. Instead, a precisely controlled doping process is used to create the desired doping profile without forming the harmful induced region. This extraction of the harmful element maintains manufacturing feasibility while improving response speed.
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
The solution effectively decreases parasitic capacitance, enhancing the response speed of ESD protection devices and maintaining high electrostatic discharge capability, thus improving the reliability and service life of integrated circuit chips.
Implementation Method 1
forming an additional doped layer... specific doping concentrations... which invert induced doped regions and create depleted extension regions
Implementation Method 2
formed by specific doping concentrations and epitaxial growth methods
Data Source
AI summary
Disclosed is a method for manufacturing an ESD protection device. The ESD protection device includes a rectifier diode and an open-base bipolar transistor, the anode of the rectifier diode is the first doped region and the cathode of the rectifier diode is the semiconductor substrate, the emitter region, base region and collector region of the open-base bipolar transistor are the second doped region, the epitaxial semiconductor layer and semiconductor substrate, respectively, the first doped region and the second doped region extend through the doped region into the epitaxial semiconductor layer by a predetermined depth. The doped region can suppress the induced doped region around the second doped region, so that the parasitic capacitance of the open-base bipolar transistor is reduced and the response speed is improved.