Bottom Anode Schottky Diode for Heat Dissipation
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Solution Overview
Problem
Conventional Schottky diodes with a vertical structure and cathode at the bottom of the substrate face limitations in high voltage applications, particularly in portable devices, due to compatibility issues with assembly configurations, heat dissipation challenges, and increased assembly complexity and cost.
Innovation Solution
A bottom-anode Schottky diode configuration with a combined anode-sinker connected to the substrate and a buried Schottky contact, featuring a reduced cell pitch and planar diode structure, which reduces anode inductance, minimizes source resistance, and enhances high gain and high frequency applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional vertical Schottky diodes with cathode at the bottom of substrate are used, then the device structure is simple, but the assembly compatibility is poor and heat dissipation is limited
Solution Approach 1:
The patent inverts the conventional Schottky diode structure by placing the anode at the bottom of the substrate instead of the cathode. This inversion allows the anode to be directly connected to the heat sink and substrate, improving assembly compatibility for high voltage applications while maintaining structural simplicity. The bottom anode configuration enables direct thermal coupling without requiring electrical isolation of the heat sink.
Solution Approach 2:
The patent transitions from a conventional vertical current flow configuration to a lateral current flow configuration. The current path extends laterally from the bottom anode through the substrate to the cathode contact at the top surface, changing the dimensional orientation of the current path and enabling better integration with standard assembly configurations.
2Temperature
If vertical Schottky diodes with cathode at bottom are used, then manufacturing process is straightforward, but heat dissipation capability is reduced
Solution Approach 1:
By inverting the diode structure to place the anode at the bottom, the patent enables direct thermal coupling between the anode and the substrate/heat sink. This configuration allows heat generated at the anode (where power dissipation occurs) to be conducted directly through the substrate, significantly improving heat dissipation capability while using standard semiconductor manufacturing processes.
3Speed
If bottom anode Schottky diode configuration is implemented, then anode inductance is reduced, but device structure becomes more complex
Solution Approach 1:
The bottom anode configuration places the anode contact at the substrate level, minimizing the loop area for high-frequency current paths. This inversion of the conventional structure reduces parasitic inductance associated with the anode connection, improving frequency response and speed while the complexity is confined to the contact configuration rather than the overall device architecture.
4Reliability
If conventional Schottky diode structure is used, then fabrication process is simple, but reverse leakage current increases at high voltage
Solution Approach 1:
The patent implements localized P+ doped regions at the periphery of the Schottky contact area to create lateral depletion regions. These localized doped regions provide electrical shielding that reduces reverse leakage current at the edges of the Schottky barrier, improving reliability at high voltages while adding minimal complexity to the fabrication process through selective ion implantation or diffusion.
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 enables reduced anode inductance, minimized source resistance, low reverse leakage, high breakdown voltage, scalability for both high and low voltage applications, and reduced latch-up possibilities, while maintaining low leakage through a shielding scheme that pinches off the cathode and Schottky contact regions.
Implementation Method 1
an anode to substrate connection formed by a sinker dopant region disposed at a depth in the semiconductor substrate and the sinker dopant region covered by a buried Schottky barrier metal
Implementation Method 2
the sinker dopant region depleting the cathode region in applying a reverse bias voltage for blocking a leakage current
Data Source
AI summary
This invention discloses a bottom-anode Schottky (BAS) diode that includes an anode electrode disposed on a bottom surface of a semiconductor substrate. The bottom-anode Schottky diode further includes a sinker dopant region disposed at a depth in the semiconductor substrate extending substantially to the anode electrode disposed on the bottom surface of the semiconductor and the sinker dopant region covered by a buried Schottky barrier metal functioning as a Schottky anode. The BAS diode further includes a lateral cathode region extended laterally from a cathode electrode near a top surface of the semiconductor substrate opposite the Schottky barrier metal wherein the lateral cathode region doped with an opposite dopant from the sinker dopant region and interfacing the sinker dopant region whereby a current path is formed from the cathode electrode to the anode electrode through the lateral cathode region and the sinker dopant region in applying a forward bias voltage and the sinker dopant region depleting the cathode region in applying a reverse bias voltage for blocking a leakage current.