Polysilicon Field Transistor Structure for Custom Foundry Components
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Solution Overview
Problem
Semiconductor foundries face challenges in producing custom semiconductor components that are not part of their standard library, as they are unwilling or unable to alter their processes on a customer-by-customer basis, leading to a need for new components manufactured according to existing foundry processes.
Innovation Solution
A field transistor structure is developed, comprising a semiconductor substrate, a metal gate, a polycrystalline silicon layer, and metal portions, with a thin metal layer or combination of metal layers electronically coupled to the polysilicon layer and semiconductor substrate, allowing for multiple circuit functions such as low-performance FETs, one-time programmable memory, and frequency-dependent resistors, by modifying conventional gate region processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If foundries use standard library components and common processes for manufacturing, then manufacturing efficiency and cost-effectiveness are improved, but the ability to produce custom semiconductor components is reduced
Solution Approach 1:
The patent applies universality by designing a field transistor structure that can serve multiple circuit functions (low-performance FETs, one-time programmable memory, frequency-dependent resistors) within a single manufacturing process. This allows foundries to produce diverse custom components without altering their standard processes, thereby maintaining manufacturing efficiency while increasing adaptability to customer needs
2Adaptability or versatility
If foundries alter their process steps on a customer-by-customer basis, then the ability to meet custom component needs is improved, but manufacturing complexity and costs increase
Solution Approach 1:
The field transistor structure enables multiple custom circuit functions to be achieved through a single universal manufacturing process. By designing the transistor with specific structural characteristics (thin metal layer, polysilicon layer configuration, gate structure), the same process can produce different functional components, eliminating the need for customer-specific process alterations and reducing manufacturing complexity
3Adaptability or versatility
If a thin metal layer is added between the polysilicon layer and semiconductor substrate, then multiple circuit functions are enabled, but device structure complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the transistor structure into distinct functional layers: a thin metal layer for electrical coupling, a polysilicon layer for structural and functional properties, and a gate structure for control. This segmentation allows each layer to contribute specifically to different circuit functions while maintaining overall structural organization and manageability
Solution Approach 2:
The field transistor structure employs composite materials by combining different material layers (metal, polysilicon, dielectric) with complementary properties. The thin metal layer provides electrical conductivity, the polysilicon layer offers structural stability and semiconducting properties, and the gate material provides control functionality. This composite approach enables multiple circuit functions while keeping the overall device structure relatively simple through material property optimization
Data Source
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AI summary
According to embodiments of the invention, a field transistor structure is provided. The field transistor structure includes a semiconductor substrate, a metal gate, a polycrystalline silicon (polysilicon) layer, and first and second metal portions. The polysilicon layer has first, second, third, and fourth sides and is disposed between the semiconductor substrate on the first side and the metal gate on the second side. The polysilicon layer is also disposed between the first and second metal portions on the third and fourth sides. According to some embodiments of the present invention, the field transistor structure may also include a thin metal layer disposed between the polysilicon layer and the semiconductor substrate. The thin metal layer may be electronically coupled to each of the first and second metal portions.