Vertical Power Transistor Die with Deep Trench Isolation
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Solution Overview
Problem
Existing semiconductor dies with vertical power transistor devices face challenges in decoupling lateral and vertical devices, leading to potential instability and unsafe operation due to shared backside potentials.
Innovation Solution
Incorporating deep trench isolation and a shielding field electrode between the lateral and vertical devices, allowing for independent potential adjustment and stabilization, while also reusing process steps for integrated power device integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lateral and vertical devices share the same backside potential in a semiconductor die, then device integration is simplified, but operational stability and safety deteriorate due to potential interference and instability
Solution Approach 1:
The semiconductor die is segmented into multiple isolation regions by deep trench structures that divide the backside into electrically independent zones. Each zone can have independent potential control, allowing the lateral device and vertical device to operate with different backside potentials, thereby preventing interference while maintaining integration benefits
Solution Approach 2:
A deep trench isolation structure filled with conductive material acts as an intermediary element between the lateral device and vertical device. This isolation structure enables independent potential adjustment for each device type, serving as a mediator that allows both devices to coexist without electrical interference while maintaining separate potential domains
2Reliability
If deep trench isolation is introduced to decouple lateral and vertical devices, then operational stability improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The deep trench isolation structure serves multiple functions simultaneously: it provides electrical isolation between lateral and vertical devices, enables independent potential control, acts as a physical barrier, and facilitates separate backside contact formation. This multi-functionality reduces the need for additional separate structures, thereby limiting the increase in overall device complexity despite the added isolation requirements
3Reliability
If deep trench isolation is used to separate lateral and vertical devices, then potential interference is reduced, but manufacturing steps and process complexity increase
Solution Approach 1:
The formation of deep trench isolation structures is merged with the formation of backside contacts and potential wells in a coordinated manufacturing process. The isolation trenches are etched and filled with conductive material in integration with the backside contact formation steps, allowing multiple functions to be achieved in a unified process flow rather than as separate sequential steps, thereby limiting the increase in manufacturing complexity
Data Source
AI summary
The disclosure relates to a semiconductor die (1), comprising a vertical power transistor device (2), the vertical power transistor device having a source region (3) and a drain region (4) at opposite sides of a semiconductor body (10), and a lateral transistor device (20), the lateral transistor device having a body region (221) with a lateral channel region (221.1), as well as a source and a drain region formed at a frontside of the semiconductor body, wherein a deep trench (305) is arranged laterally between the vertical power transistor device (2) and the lateral transistor device (20), forming a deep trench isolation (306).