Schottky Device Multi-Concentration Doping for Low Forward Voltage
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Solution Overview
Problem
Schottky devices face limitations in high voltage applications due to increased forward voltage and decreased switching speed, along with high current leakage and low reverse blocking capabilities, which are costly and inefficient to manufacture.
Innovation Solution
The development of a Schottky device with a semiconductor material having a first conductivity type and a second conductivity type, featuring a cavity with mesa structures and multi-concentration dopant regions, along with a method that includes forming trenches, dielectric layers, and polysilicon layers to create a Schottky device with improved conductivity modulation and reduced forward voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If techniques for increasing the breakdown voltage of a Schottky device are used, then the breakdown voltage is improved, but the forward voltage increases and switching speed decreases
Solution Approach 1:
The patent applies local quality by creating multi-concentration dopant regions with different doping levels in specific areas of the semiconductor structure. High concentration dopant regions are positioned near the Schottky contact to reduce forward voltage and improve switching speed, while lower concentration regions extend deeper to maintain high breakdown voltage. This spatial variation in dopant concentration allows simultaneous optimization of both forward voltage characteristics and breakdown voltage without compromising switching speed.
2Ease of manufacture
If conventional Schottky device structures are used, then manufacturing is simpler, but current leakage is high and reverse blocking capability is low
Solution Approach 1:
The patent employs parameter changes by systematically varying the dopant concentration parameters across different regions of the semiconductor structure. The multi-concentration dopant profile uses at least two different dopant concentrations, with the first concentration near the Schottky contact and the second concentration at greater depths. This parameter variation reduces reverse leakage current and enhances reverse blocking capability while maintaining compatibility with existing manufacturing processes through standard diffusion or implantation techniques.
3Strength
If Schottky devices are configured to support increased breakdown voltage, then breakdown voltage is improved, but the forward voltage drop increases significantly
Solution Approach 1:
The patent applies local quality by creating high concentration dopant regions positioned close to the Schottky metal-semiconductor contact interface. These localized high-doping regions reduce the forward voltage drop by modifying the depletion layer characteristics at the critical contact area, while the overall device structure maintains high breakdown voltage through the extended lower concentration regions. This spatial differentiation allows independent optimization of forward voltage and breakdown voltage characteristics.
Solution Approach 2:
The patent utilizes another dimension by transitioning from a uniform dopant concentration approach to a vertically stratified multi-concentration profile. The dopant concentration varies with depth from the surface, creating a gradient structure where high concentration regions are positioned at shallow depths near the contact and lower concentration regions extend to greater depths. This dimensional variation in dopant distribution enables simultaneous achievement of low forward voltage drop and high breakdown voltage.
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 achieves a balance of low forward voltage, high breakdown voltage, and reduced leakage current, while maintaining fast switching speed and being cost-efficient, compatible with existing manufacturing processes.
Implementation Method 1
The solution achieves a balance of low forward voltage, high breakdown voltage, and reduced leakage current, while maintaining fast switching speed
Data Source
AI summary
A method for manufacturing a semiconductor component includes forming first mesa and second mesa structures from a semiconductor material by etching trenches into the semiconductor material. A doped region having a multi-concentration dopant profile is formed in at least the first mesa structure and doped polysilicon is formed in the trenches. The trenches are formed in a geometric pattern. A contact having three contact types is formed, wherein a first contact type is formed to the first mesa structure, a second contact type is formed to the second mesa structure, and a third contact type is formed to the doped polysilicon in the trenches. The first contact type has electrical properties between a conventional Schottky contact and a conventional Ohmic contact without being a conventional Schottky contact or a conventional Ohmic contact, the second contact type is a Schottky contact, the third contact type is an Ohmic contract.