Solid-State Diode With Segmented PN Junctions for Leakage Control
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Solution Overview
Problem
Conventional solid-state diodes suffer from parasitic effects that restrict their functional reliability, particularly in voltage stabilization and overvoltage protection applications, due to unpredictable breakdown locations and significant production-related scatter in breakdown voltage.
Innovation Solution
The solid-state diode design features self-aligning pn junctions with masking areas ensuring the cathode and anode regions are at the same electrical potential, creating a constricted junction and a parasitic MIS capacitor to counteract GIDL effects, and using ion implantation for precise doping with different mobilities to control the expansion of doped regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the width of pn junction is kept relatively narrow to limit breakdown location, then breakdown location is constrained, but parasitic effects still occur restricting functional reliability
Solution Approach 1:
The pn junction is segmented into multiple regions with different doping concentrations and geometries. The junction is divided into a first region with higher doping concentration and a second region with lower doping concentration, creating distinct functional zones that control breakdown location and reduce parasitic effects.
Solution Approach 2:
Different regions of the pn junction are given different local properties through varying doping concentrations. The first region has higher doping concentration for one function while the second region has lower doping concentration for another function, allowing optimization of different areas for different purposes.
2Ease of manufacture
If conventional diode design with large width p and n regions is used, then manufacturing is easier, but breakdown location cannot be foreseen and parasitic currents increase
Solution Approach 1:
The doping process is performed in a predetermined sequence with the first dopant applied before the second dopant. This preliminary action establishes the doping concentration gradient before final device formation, ensuring precise breakdown voltage control while maintaining manufacturing simplicity.
Solution Approach 2:
The sequential doping process allows the device structure to self-organize the doping distribution. The first dopant diffuses to create a base profile, then the second dopant modifies it in situ, eliminating the need for complex post-processing alignment steps.
3Reliability
If Zener diode combines tunnel breakthrough and avalanche breakthrough mechanisms, then temperature coefficient is reduced, but production-related scatter in breakdown voltage increases
Solution Approach 1:
The doping concentration is used as a key parameter to control the breakdown characteristics. By precisely controlling the doping concentration in the first and second regions, the breakdown voltage can be tuned to achieve the desired temperature coefficient while minimizing production scatter through optimized doping profiles.
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 design ensures reliable and reproducible functionality with reduced leakage current and controlled breakdown voltage, providing enhanced circuit technology properties for voltage stabilization and protection against overvoltages.
Implementation Method 1
a tunnel breakthrough and an avalanche breakthrough
Implementation Method 2
an avalanche breakthrough
Implementation Method 3
the n-doped cathode region is generated by an ion implantation
Data Source
Figure 1~3
Figure 4~6
Figure 7~8
AI summary
The diode has masking regions (14) made of a material impermeable to ion implantation first masking material, which is formed on upper side of a semiconductor substrate (12). Two opposite limiting edge portions are provided in masking regions. An n-doped cathode zone (22) with cathode terminal box (34), and p-doped anode zone (30) with anode terminal box (36) are provided in substrate in a state projecting into the space between boundary edge portions of masking regions. Either the cathode terminal box or anode terminal box lies at the same electrical potential in masking regions.