Intrinsic Replacement Channel TFET Fin Fabrication
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Solution Overview
Problem
Current semiconductor device fabrication methods for tunneling field effect transistors (TFETs) face challenges in achieving efficient channel replacement and gate integration, which affects the device's switching performance and reliability.
Innovation Solution
A semiconductor device fabrication process involving the formation of a diode fin with a sacrificial channel, followed by the removal of the sacrificial gate and channel to create an intrinsic replacement channel, allowing for the formation of a TFET fin with a replacement gate, enabling efficient channel replacement and improved device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sacrificial channel is used in conventional TFET fabrication, then the channel replacement process becomes simpler, but the manufacturing precision and reliability of the final device deteriorate due to alignment issues between the replacement channel and doped fins
Solution Approach 1:
The patent applies preliminary action by forming the intrinsic replacement channel before the doped source and drain fins are fully processed. The replacement channel is grown as an epitaxial layer on the substrate, and then the doped fins are formed around it. This sequence ensures that the replacement channel is already in its final position and dimensions before the doped fins are created, eliminating subsequent alignment issues that would occur if the channel were replaced after fin formation.
Solution Approach 2:
The patent inverts the conventional fabrication sequence by forming the replacement channel first and then creating the doped fins around it, rather than forming fins first and then replacing the channel. This inversion of the process sequence fundamentally resolves the alignment problem by making the channel the reference structure upon which the fins are built, rather than trying to fit a replacement channel into a pre-formed fin structure.
2Adaptability or versatility
If the intrinsic replacement channel is formed after removing the sacrificial channel, then the TFET structure can be created, but the process complexity increases and manufacturing precision deteriorates
Solution Approach 1:
The intrinsic replacement channel is formed as a preliminary structure before the doped fins are processed. By growing the replacement channel epitaxially on the substrate first, the patent establishes the channel region in advance, which then serves as the template for forming the doped source and drain fins. This preliminary formation simplifies the overall process by eliminating the need for sacrificial channel deposition, patterning, and removal steps.
3Productivity
If conventional TFET fabrication methods are used, then the device can be manufactured, but the switching performance and reliability are reduced due to alignment misalignment
Solution Approach 1:
By forming the intrinsic replacement channel before the doped fins, the patent ensures perfect alignment between the channel and the source/drain regions. This preliminary channel formation establishes the exact position and dimensions of the active channel region, which then guides the formation of the doped fins. The result is a device with optimal alignment that maximizes switching performance and reliability, eliminating the alignment errors that plague conventional approaches.
Solution Approach 2:
The inverted process sequence of forming the replacement channel first and then the doped fins around it fundamentally improves device reliability. This inversion makes the channel the master reference structure, ensuring that the doped fins are precisely positioned relative to the channel. The resulting perfect alignment optimizes carrier transport and switching characteristics, significantly improving device performance compared to conventional methods.
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
This process enhances the switching characteristics and reliability of TFETs by forming a replacement channel that aligns with the p-fin and n-fin, improving current flow and device operation.
Implementation Method 1
epitaxially growing a fin layer from an upper surface of the semiconductor substrate
Implementation Method 2
band-to-band tunneling occurs when the conduction band of the intrinsic region aligns with the valence band of the P region. Electrons from the valence band of the p-type region tunnel into the conduction band of the intrinsic region
Data Source
AI summary
A semiconductor structure includes a substrate and an intrinsic replacement channel. A tunneling field effect transistor (TFET) fin may be formed by the intrinsic replacement channel, a p-fin and an n-fin formed upon the substrate. The p-fin may serve as the source of the TFET and the n-fin may serve as the drain of the TFET. The replacement channel may be formed in place of a sacrificial channel of a diode fin that includes the p-fin, the n-fin, and the sacrificial channel at the p-fin and n-fin junction.