Vertical Discrete Devices With Trench Contacts
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Solution Overview
Problem
Conventional vertical discrete semiconductor devices face challenges in achieving low on-resistance (RON) and small area requirements due to the need for backside drain/cathode contact, which complicates co-packaging with integrated circuit dies, especially when lateral devices like LDMOS are not suitable.
Innovation Solution
The implementation of trench contacts filled with conducting materials like tungsten that connect the substrate to the topside surface, reducing the area required for drain contact and maintaining low RON by converting the backside drain to a topside contact, thereby allowing for efficient co-packaging with integrated circuit dies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If backside drain contact is used in conventional vertical discrete devices, then low on-resistance can be achieved, but the device area increases and co-packaging with integrated circuit dies becomes complicated
Solution Approach 1:
The patent transitions the drain contact from the backside (2D plane) to the topside surface through vertical trench structures (3D dimensionality change). Trenches are formed extending from the topside surface through the device layers to contact the drain region, allowing drain access on the same side as source and gate contacts, thereby reducing the need for backside contact area while maintaining low on-resistance.
Solution Approach 2:
Instead of contacting the drain from the backside as in conventional devices, the patent inverts the approach by creating topside-accessible drain contacts through vertical trenches. This inversion of the contact geometry allows all three terminals (source, gate, drain) to be accessible from the topside, simplifying co-packaging while maintaining electrical performance.
2Reliability
If backside drain contact is used in conventional vertical discrete devices, then low on-resistance can be achieved, but co-packaging with integrated circuit dies becomes difficult
Solution Approach 1:
By transitioning from backside contact (2D arrangement) to topside trench contacts (3D arrangement), the patent enables all device terminals to be accessible from the same side, making co-packaging with integrated circuit dies feasible while maintaining the low on-resistance characteristic of vertical device structures.
Solution Approach 2:
The topside trench contact structure serves multiple functions: it provides drain access on the same side as other terminals, maintains low on-resistance through direct vertical contact, and enables co-packaging configurations. This multi-functional design increases adaptability for various packaging applications.
3Adaptability or versatility
If lateral devices like LDMOS are used to enable same-side contacts, then co-packaging becomes easier, but on-resistance increases and device area expands
Solution Approach 1:
The patent maintains the vertical device architecture (superior for low on-resistance) while introducing vertical trench contacts from the topside to access the drain region. This dimensional approach allows same-side contact accessibility like lateral devices but preserves the low on-resistance advantage of vertical structures by maintaining the vertical current flow path.
Data Source
AI summary
The present technology is related generally to vertical discrete devices with a trench at the topside of the vertical discrete devices. The trench is filled with a conducting material. In this approach, a drain or cathode of the vertical discrete devices is electrically connected to the topside to result in a small area with low RON*AREA.