Schottky Contact Power Transistor SOA
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Solution Overview
Problem
Conventional power transistors face limitations in safe operating area (SOA) due to parasitic bipolar transistor activation, leading to destructive failures and increased on-state resistance, which complicates device design and increases costs.
Innovation Solution
The introduction of Schottky or Schottky-like contacts as source and/or drain regions in power transistor structures, eliminating parasitic n-p-n bipolar transistors and reducing device size, while providing improved electrical coupling and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power transistor structures are used, then parasitic bipolar transistor activation is avoided by reducing operating voltage, but on-state resistance increases and safe operating area is limited
Solution Approach 1:
The patent changes the physical and chemical parameters of the contact structure by introducing Schottky or Schottky-like contacts with specific barrier heights and interfacial dopant segregation layers. This modifies the electrical characteristics to reduce on-state resistance while preventing parasitic bipolar activation, thereby expanding the safe operating area without energy loss compromise.
Solution Approach 2:
The patent employs composite contact structures combining metal layers with interfacial dopant segregation layers forming Schottky barriers. This composite approach creates optimized electrical properties that simultaneously achieve low on-state resistance and high reliability by controlling the interaction between metal and semiconductor materials at the interface.
2Reliability
If deep p+ regions or recessed contact structures are introduced to alleviate SOA limitation, then safe operating area improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the essential function of deep p+ regions and recessed contacts by implementing Schottky or Schottky-like contacts at the surface level. This eliminates the need for complex deep implantation or recessed structures while achieving the same SOA improvement through the Schottky barrier mechanism, thereby reducing device complexity.
Solution Approach 2:
Instead of using deep p+ regions or recessed contacts to control parasitic bipolar effects, the patent inverts the approach by using Schottky contacts with specific barrier heights and interfacial dopant segregation to achieve the same effect. This alternative methodology simplifies the structure while maintaining or improving SOA characteristics.
3Reliability
If Schottky or Schottky-like contacts are used, then parasitic bipolar transistor activation is prevented and on-state resistance is reduced, but manufacturing process complexity may increase
Solution Approach 1:
The patent incorporates interfacial dopant segregation layers during the contact formation process itself, performing the doping action preliminarily as the contact is being created. This eliminates the need for separate deep doping steps or complex subsequent processing, thereby maintaining ease of manufacture while achieving the desired Schottky barrier characteristics for improved reliability.
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
This approach enhances the safe operating area, reduces on-state resistance, and decreases the likelihood of catastrophic failures, resulting in more reliable and efficient power transistors with reduced manufacturing complexity and cost.
Implementation Method 1
at least one of the source region and the drain region is a Schottky or Schottky-like contact
Data Source
AI summary
Devices, structures, and methods thereof for providing a Schottky or Schottky-like contact as a source region and/or a drain region of a power transistor are disclosed. A power transistor structure comprises a substrate of a first dopant polarity, a drift region formed on or within the substrate, a body region formed on or within the drift region, a gate structure formed on or within the substrate, a source region adjacent to the gate structure, a drain region formed adjacent to the gate structure. At least one of the source region and the drain region is formed from a Schottky or Schottky-like contact substantially near a surface of the substrate, comprising a silicide layer and an interfacial dopant segregation layer. The Schottky or Schottky-like contact is formed by low-temperature annealing a dopant segregation implant in the source and/or drain region.