Trench Schottky Diode Insulating Layer Segmentation
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Solution Overview
Problem
Schottky barrier diodes experience increased leakage current at reverse bias due to the lowering of the Schottky barrier under high electric fields, which is mitigated by using high work function metals, but this increases forward voltage drop and turn-on power loss.
Innovation Solution
A trench Schottky barrier diode is fabricated with a thinner insulating layer on the upper sidewall of trenches to suppress reverse leakage current and a thicker insulating layer on the lower sidewall and bottom to enhance device reliability, effectively forming a depletion region and improving blocking capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a high work function metal is used to provide a high Schottky barrier, then reverse leakage current is reduced, but forward voltage drop and turn-on power loss increase
Solution Approach 1:
The patent segments the insulating layer into two distinct portions with different thicknesses: a first portion with greater thickness and a second portion with lesser thickness. This segmentation allows different regions to serve different functions - the thicker first portion suppresses reverse leakage current, while the thinner second portion reduces forward voltage drop and turn-on power loss, thereby resolving the technical contradiction between reducing reverse leakage and minimizing energy loss.
Solution Approach 2:
The patent applies local quality by creating non-uniform insulating layer thickness across different locations. The first portion has greater thickness specifically positioned to address reverse leakage current suppression, while the second portion has lesser thickness optimized for reducing forward voltage drop. This localized differentiation of insulating layer properties enables simultaneous optimization of both contradictory performance parameters.
2Object-generated harmful factors
If the insulating layer thickness is increased to suppress reverse leakage current, then blocking capability improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The insulating layer is segmented into two portions with different thicknesses formed through a two-stage process. This segmentation achieves effective reverse leakage suppression through the thicker first portion while maintaining manageable device complexity by using a systematic fabrication approach with sequential deposition and patterning steps.
Solution Approach 2:
The patent employs preliminary action by first forming the thicker first portion of the insulating layer to establish the primary barrier against reverse leakage current, then subsequently forming the thinner second portion. This sequential approach simplifies the overall manufacturing process by breaking down the complex task of creating non-uniform thickness into manageable stages, reducing device complexity while achieving the desired electrical performance.
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 effectively reduces reverse leakage current while maintaining breakdown voltage, thereby improving the reliability and performance of the Schottky barrier diode.
Implementation Method 1
effectively forming a depletion region and improving blocking capability
Data Source
AI summary
A Schottky barrier diode and fabricating method thereof are disclosed. A semiconductor substrate may have a first surface and a second surface positioned oppositely to be provided. Several trenches are formed on the first surface. Each trench has a sidewall with a first depth and a first bottom surface. An insulating material is formed on the first surface of the semiconductor substrate and on the sidewall and the first bottom surface of each trench, wherein the insulating material has a first thickness on the sidewall. The insulating material on the sidewall is patterned to define a second bottom surface having a second depth smaller than the first depth, and the removed portion of the insulating material on the sidewall has a second thickness smaller than the first thickness. Afterward, a contact metal layer is at least formed on the first surface between adjacent trenches.