Schottky Device Mesa Structures Multi-Concentration Doping
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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 Schottky devices with mesa structures featuring multi-concentration impurity profiles and trenches that modulate conductivity, reducing forward voltage and increasing breakdown voltage while maintaining switching speed, achieved through specific doping and etching processes.
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 semiconductor substrate is divided into multiple regions with different doping concentrations, creating a segmented structure that allows different parts to perform different functions: high-doped regions provide low forward voltage and fast switching, while low-doped regions provide high breakdown voltage
Solution Approach 2:
Different regions of the Schottky device are assigned different doping concentrations to create local variations in electrical properties. The high-doped regions near the Schottky contact optimize for low forward voltage drop and fast switching, while low-doped regions farther away optimize for high breakdown voltage
2Ease of manufacture
If conventional Schottky device structures are used, then manufacturing is simpler, but reverse blocking capability is low and leakage current is high
Solution Approach 1:
The invention transitions from a planar Schottky contact structure to a vertically structured device with trenches extending into the substrate. This dimensional change creates multiple interfaces and regions that work together to improve reverse blocking capability while maintaining manufacturing feasibility through standard semiconductor processing techniques
3Loss of energy
If techniques to improve forward voltage drop are used, then forward voltage is reduced, but reverse leakage current increases
Solution Approach 1:
The device structure creates local variations in doping concentration where high-doped regions near the Schottky contact minimize forward voltage drop through enhanced carrier injection, while the gradual transition to low-doped regions in the bulk provides effective reverse leakage current suppression through increased reverse bias resistance
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 approach results in Schottky devices with improved forward voltage drop, reduced leakage current, and enhanced breakdown voltage, optimizing electrical characteristics while being cost and time efficient in manufacturing.
Implementation Method 1
manufacturing mesa structures or mesa regions having stepped or multi-concentration impurity profiles
Data Source
AI summary
A Schottky device includes a plurality of mesa structures where one or more of the mesa structures includes a doped region having a multi-concentration dopant profile. In accordance with an embodiment, the Schottky device is formed from a semiconductor material of a first conductivity type. Trenches having sidewalls and floors are formed in the semiconductor material to form a plurality of mesa structures. A doped region having a multi-concentration impurity profile is formed between two trenches, where the impurity materials of the doped region having the multi-concentration impurity profile are of a second conductivity type. A Schottky contact is formed to at least one of the mesa structures having the doped region with the multi-concentration impurity profile.