Elbow Contact for FET Using Vertical Epitaxial Growth
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Solution Overview
Problem
As device scaling progresses and devices are packed more tightly, the available area for contacting the active device shrinks, leading to an increase in device contact resistance, which is detrimental as intrinsic device resistance decreases to improve performance.
Innovation Solution
A field-effect transistor (FET) design that utilizes the vertical dimension by growing a semiconductor pillar on top of the source and drain regions and forming a conductive sheath alongside the gate, increasing the contact area and reducing contact resistance by using the vertical dimension to form an elbow contact, which can increase the contact area by three times compared to conventional horizontal contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If device scaling progresses and devices are packed more tightly to increase density, then device density increases, but contact area shrinks leading to increased contact resistance
Solution Approach 1:
The patent transitions from a conventional planar contact geometry to a three-dimensional vertical contact structure. The contact extends downward from the surface along the sidewalls of the trench, utilizing the vertical dimension to increase contact area. This dimensional change allows the contact to maintain low resistance even as horizontal device pitch shrinks, directly resolving the contradiction between increased device density and maintained contact quality.
Data Source
AI summary
A field-effect transistor (FET) and method of manufacture thereof include patterning a mask above a source and drain of a FET to form holes in the mask, growing epitaxial structures from the holes in the mask, and growing a doped epitaxial shell to coat sidewalls of the epitaxial structures.