Transistor Channel Segmentation for Carrier Mobility
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Solution Overview
Problem
Current transistors face limitations in achieving high carrier mobility, which affects their performance.
Innovation Solution
A transistor design featuring a semiconductor channel layer with specific crystal plane orientations and a layered structure including insulating and conductive layers, along with a hole injection layer and metal layer, is developed. The method involves forming a stack of conductive and insulating layers on a substrate, patterning to create openings, and filling with a semiconductor layer that forms discrete channels with enhanced carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transistor structures are used, then manufacturing is simpler, but carrier mobility is limited
Solution Approach 1:
The transistor channel is segmented into multiple discrete semiconductor channels formed in separate openings through the insulating layers. Each opening contains a distinct semiconductor channel with controlled crystal orientation, allowing independent optimization of carrier mobility in each channel region.
Solution Approach 2:
Different regions of the transistor structure are assigned different material compositions and crystal orientations. The semiconductor channels are formed with specific crystal planes (e.g., (001) orientation) in specific locations to maximize carrier mobility, while insulating layers and electrodes are optimized for their respective functions.
2Reliability
If semiconductor layer is formed to fill openings completely, then channel continuity is improved, but carrier mobility decreases due to unwanted crystal orientations
Solution Approach 1:
The portion of the semiconductor layer with unwanted crystal orientation (edge-on arrangement) is removed by etching away the top surface. Only the semiconductor material with the desired crystal orientation (face-on arrangement) remaining in the openings is retained to form the active channels, ensuring high carrier mobility.
Solution Approach 2:
Instead of forming the semiconductor layer and then selecting the desired orientation, the process inverts the approach: the semiconductor layer is first formed with mixed orientations, then the unwanted orientation is removed, leaving only the desired orientation. This inversion allows precise control over the final crystal orientation of the active channels.
Data Source
AI summary
A method of forming a transistor includes: forming a stack structure including a first conductive layer, a first insulating layer, a second conductive layer, and a second insulating layer on a substrate; patterning the first insulating layer, the second conductive layer, and the second insulating layer to form at least one opening passing through the first insulating layer, the second conductive layer, and the second insulating layer; forming a semiconductor layer over the second insulating layer and filling the opening; removing the portion of the semiconductor layer over the second insulating layer, in which the portion of the semiconductor layer filled in the opening constitutes at least one semiconductor channel; and forming a third conductive layer over the semiconductor channel.