Schottky Diode Leakage Blocking at the STI Edge
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Solution Overview
Problem
Existing Schottky barrier diodes (SBDs) suffer from high leakage current, which leads to unwanted power loss and heat generation due to irregularities in the adjoining surfaces, crystal defects, and insufficient barrier height.
Innovation Solution
Implementing a resist protection structure (RPS) that overlaps with the semiconductor material and edge shallow trench isolation (STI) structure, combined with high dosage p-type or n-type impurity implantation to block leakage pathways and improve on-current (Ion) conditions, optionally with a polysilicon cap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional Schottky barrier diode structures are used, then manufacturing is simple, but leakage current is high
Solution Approach 1:
The patent segments the semiconductor device into distinct functional regions by introducing shallow trench isolation (STI) structures that divide the semiconductor layer into separate areas. This segmentation creates isolated regions that prevent leakage current pathways while maintaining controlled electrical characteristics in each segment, thereby reducing overall leakage without excessive complexity
Solution Approach 2:
The patent applies local quality by creating regions with different doping concentrations and types - specifically introducing p-type or n-type impurity regions adjacent to the Schottky barrier diode. These locally modified regions have tailored electrical properties that block leakage current at critical interfaces while preserving the low forward voltage drop characteristic of the main diode structure
2Loss of energy
If barrier height is increased to reduce leakage current, then leakage current decreases, but forward voltage drop increases
Solution Approach 1:
The patent introduces locally doped regions with specific conductivity types adjacent to the Schottky barrier diode. These localized impurity regions create potential barriers that selectively block reverse leakage current while having minimal impact on forward conduction, thus reducing energy loss during reverse bias without significantly increasing forward voltage drop
Solution Approach 2:
The patent introduces intermediate impurity regions that act as mediators between the metal electrode and the semiconductor substrate. These intermediate layers with controlled doping profiles serve as transition zones that modify the electric field distribution, reducing tunneling leakage current while maintaining efficient charge transport during forward operation
3Loss of energy
If surface irregularities and crystal defects are reduced to lower leakage current, then manufacturing precision must increase, but manufacturing complexity increases
Solution Approach 1:
The patent employs preliminary action by introducing shallow trench isolation structures and impurity regions during early fabrication stages, before final surface finishing. These pre-introduced features proactively block potential leakage pathways that would otherwise require extremely high surface precision to prevent, thereby reducing the stringent surface quality requirements while still achieving low leakage current
Solution Approach 2:
The patent introduces intermediate STI structures and doped regions that act as mediators between the metal electrode and semiconductor substrate. These intermediary layers compensate for surface irregularities and crystal defects by providing alternative low-resistance pathways and electric field management, reducing the impact of manufacturing variations on leakage current
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
Reduces leakage current and enhances the on-current performance of SBDs by effectively blocking current leakage at the metal electrode interface, leading to improved efficiency and reduced power loss.
Implementation Method 1
high dosage p-type or n-type impurity implantation to block leakage pathways
Implementation Method 2
Schottky barrier diodes (SBDs) are commonly used in modern semiconductor devices
Data Source
AI summary
Embodiments include a Schottky barrier diode (SBD) structure and method of forming the same, the SBD structure including a current blockage feature to inhibit current from leaking at an interface with a shallow trench isolation regions surrounding an anode region of the SBD structure.