Schottky Diode With Control Gate For Leakage Prevention
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Solution Overview
Problem
High voltage devices, particularly Schottky diodes, face challenges in achieving high operating voltage and preventing leakage current while maintaining fast switching characteristics, which are essential for power conversion and control applications.
Innovation Solution
The integration of a semiconductor substrate with a Schottky diode, a salicide block, and a heavily doped region that is non-contacting with the diode, along with a control gate covering the diode and doped region, enhances the operating voltage and prevents leakage current. Additionally, the use of titanium silicide, cobalt silicide, or tantalum silicide in the Schottky diode formation improves the device's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a Schottky diode is used to achieve low forward voltage drop and fast switching, then switching speed and voltage clamping performance are improved, but leakage current increases at high operating voltages
Solution Approach 1:
The device is segmented into distinct functional regions: a first doped region under the Schottky diode for low-voltage operation, and a second doped region for high-voltage operation. This segmentation allows each region to be optimized independently, enabling the Schottky diode to maintain fast switching while the second doped region suppresses leakage current at high voltages through its specific doping concentration and depth.
Solution Approach 2:
Different doping concentrations and types are applied to different locations within the semiconductor substrate. The first doped region has a first doping concentration optimized for Schottky diode performance, while the second doped region has a second doping concentration specifically designed to reduce leakage current. This local quality variation resolves the contradiction between fast switching and leakage prevention.
2Object-generated harmful factors
If the heavily doped region is positioned close to the Schottky diode to prevent leakage current, then leakage prevention is improved, but the device complexity and manufacturing precision requirements increase
Solution Approach 1:
The first and second doped regions are merged into a single continuous doped structure within the semiconductor substrate, sharing common formation processes and alignment references. This merging reduces device complexity by eliminating the need for separate fabrication steps and alignment procedures, while still achieving effective leakage current prevention through the combined doping profile.
3Reliability
If the Schottky diode is integrated with a MOS transistor for protection function, then protection capability is improved, but the manufacturing precision and process complexity increase
Solution Approach 1:
The semiconductor substrate is designed to serve multiple functions: it hosts both the Schottky diode for voltage clamping and fast switching, and the MOS transistor for protection functions. The shared substrate and common doping regions enable both devices to operate simultaneously with coordinated protection capability, achieving multi-functionality without proportionally increasing manufacturing precision requirements.
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 results in higher operating voltage and prevents leakage current, while the integration with a MOS transistor accelerates turn-on speed, providing effective protection against high voltage feedback.
Implementation Method 1
Schottky diode's voltage drop at a forward bias of about 1 mA is in the rage of 0.15 V to 0.45 V
Implementation Method 2
at least a first heavily doped region having a first conductive type formed in the semiconductor substrate under the SAB
Data Source
AI summary
A high voltage device having Schottky diode includes a semiconductor substrate, a Schottky diode formed on the semiconductor substrate, at least a first doped region having a first conductive type formed in the semiconductor substrate and under the Schottky diode, and a control gate positioned on the semiconductor substrate. The control gate covers a portion of the Schottky diode and the first doped region positioned on the semiconductor substrate.