Semiconductor Contact Window Definition via Dielectric Segmentation
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Solution Overview
Problem
Conventional methods for manufacturing Schottky barrier device contacts lack the precision required to create features below a certain size, limiting the miniaturization of contact metal areas and thereby constraining the performance characteristics of semiconductor devices.
Innovation Solution
A method involving a first dielectric layer with a first opening on a semiconductor surface, where a second dielectric layer is used to define a smaller contact window by partially filling and then removing the first dielectric layer, allowing for precise control of contact metal geometry through epitaxial or dielectric regrowth, enabling contact metal lengths less than 0.01 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photo-resist etching process is used to create contact windows, then the manufacturing process is simple and easy to implement, but the manufacturing precision is insufficient to create features below a certain size
Solution Approach 1:
The manufacturing process is divided into multiple sequential steps: first forming a contact window through photo-resist etching, then selectively depositing dielectric material in the opening, performing epitaxial regrowth, and finally removing the dielectric material to define the precise contact window. This segmentation allows each step to contribute to the final precision without requiring the entire process to achieve the target dimension in one step.
Solution Approach 2:
The dielectric material is deposited and epitaxial regrowth is performed before the final contact window definition. These preliminary actions prepare the semiconductor surface and create precise geometric boundaries that guide the subsequent contact metal deposition, ensuring the final contact window achieves the required sub-0.01 μm precision.
2Speed
If the area of contact metal at the semiconductor surface is reduced to increase device speed, then the device speed improves, but the manufacturing precision required to define such small areas becomes difficult to achieve
Solution Approach 1:
Dielectric material serves as an intermediary substance that is selectively deposited within the contact window opening and used to define the final contact metal geometry. This intermediary layer enables precise definition of sub-0.01 μm contact areas by providing a controllable geometric boundary that is easier to manufacture with standard processes.
Solution Approach 2:
The patent transitions from defining contact geometry in a single planar dimension to using vertical layering with dielectric material deposition and epitaxial regrowth. This dimensional approach allows precise lateral definition of contact windows by controlling vertical material deposition and removal, achieving precision unattainable through planar etching alone.
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
Enables the precise manufacturing of semiconductor contacts with geometries that enhance the performance of devices like HEMTs and MESFETs by allowing for smaller contact metal areas, thereby improving device speed and efficiency.
Implementation Method 1
epitaxial or base dielectric layer regrowth is grown on the exposed portions of the first surface of the semiconductor layer
Data Source
AI summary
A first dielectric layer including a first opening is provided on a first surface of a semiconductor layer. A second dielectric layer is provided on top of the first dielectric layer in the first opening. A first portion of the second dielectric layer is then removed, such that a second portion of the second dielectric layer remains in the first opening. The first dielectric layer is then removed, leaving only the second portion of the second dielectric layer on the surface of the semiconductor layer. An epitaxial layer or a base dielectric layer is grown on the exposed portions of the first surface of the semiconductor layer not covered by the second portion of the second dielectric layer. The second portion of the second dielectric layer is then removed to define one or more contact windows, and a contact metal is deposited in the one or more contact windows.