Schottky Diode With Segmented Doping For Motor Vehicle Generators
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Solution Overview
Problem
Schottky diodes are not suitable for motor vehicle generator systems due to high reverse current, strong voltage dependence, and poor robustness, despite offering lower forward voltage compared to PN diodes.
Innovation Solution
A semiconductor system combining a PN diode with a Schottky diode, utilizing different doping profiles to achieve a Schottky diode with a higher breakdown voltage and reduced electrical field strength at the Schottky contact, eliminating the need for complex trench technology and minimizing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If Schottky diodes are used in motor vehicle generator systems, then forward voltage is reduced (0.5V to 0.6V), but reverse current increases significantly
Solution Approach 1:
The Schottky diode structure is segmented into multiple regions with different doping concentrations. The patent introduces a first doped region with first doping concentration and a second doped region with second doping concentration, creating distinct functional zones that separately manage forward conduction and reverse leakage characteristics
Solution Approach 2:
Different regions of the Schottky diode are assigned different doping concentrations to achieve localized optimization. The first doped region has higher doping concentration for low forward voltage, while the second doped region has lower doping concentration for reduced reverse current, allowing each region to perform its specific function optimally
2Speed
If Schottky diodes are used in motor vehicle generator systems, then switching speed is improved, but robustness deteriorates at high temperature
Solution Approach 1:
The patent introduces a temperature-dependent compensation mechanism through the dual-doped structure. The different doping concentrations create opposing temperature coefficients that dynamically compensate for each other, maintaining stable reverse current characteristics across temperature variations and improving high-temperature robustness
3Object-generated harmful factors
If complex trench technology is used to reduce leakage current, then reverse current is suppressed, but manufacturing complexity increases
Solution Approach 1:
Instead of using complex trench structures, the patent achieves leakage current suppression by changing the doping concentration parameter. The second doped region is designed with a lower doping concentration than the first doped region, which modifies the electrical field distribution and reduces the barrier lowering effect, thereby suppressing reverse current through parameter optimization rather than structural complexity
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 provides a Schottky diode with low leakage current, low forward voltage, and high robustness, suitable for motor vehicle generator systems, with reduced manufacturing complexity and effective suppression of the barrier lowering effect.
Implementation Method 1
a Schottky contact between a metal layer (4) and the n-epitaxial layer (2)
Implementation Method 2
The Schottky effect, or barrier lowering effect, which is responsible for the high reverse currents, is thus partially shielded
Implementation Method 3
the space charge regions expand with increasing voltage and collide in the middle of the area between adjacent p-wells 3
Data Source
AI summary
A semiconductor system of a Schottky diode is described having an integrated PN diode as a clamping element, which is suitable in particular as a Zener diode having a breakdown voltage of approximately 20 V for use in motor vehicle generator systems. The semiconductor system of the Schottky diode includes a combination of a Schottky diode and a PN diode. The breakdown voltage of the PN diode is much lower than the breakdown voltage of the Schottky diode, the semiconductor system being able to be operated using high currents during breakdown operation.