Fin-Based Semiconductor Device Corner Rounding via Point Defect Migration
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Solution Overview
Problem
The etching process for fin-based semiconductor devices damages sidewall surfaces and introduces sharp corners, leading to reduced carrier mobility and subthreshold characteristics, which existing methods like hydrogen annealing struggle to address effectively due to a narrow temperature/pressure window and limitations in corner rounding control.
Innovation Solution
A method involving the creation of a supersaturation of point defects in fin-based semiconductor devices, followed by annealing and cooling, allows semiconductor atoms to migrate, thereby smoothing sidewalls and rounding corners, with improved control over corner radius and reduced thermal budget.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hydrogen annealing is used to smooth sidewalls and round corners, then surface roughness is reduced, but the temperature/pressure window is narrow and control of corner rounding radius is difficult
Solution Approach 1:
The patent changes the fundamental parameters of the annealing process by introducing a controlled atmosphere with specific oxygen partial pressure and using a two-stage annealing process (first stage: smoothing at lower temperature; second stage: corner rounding at higher temperature), thereby expanding the usable temperature/pressure window and enabling independent control of surface roughness and corner radius
Solution Approach 2:
The patent performs preliminary surface smoothing in the first annealing stage before attempting corner rounding, preparing the surface in advance to enable better control during the subsequent corner rounding stage
2Reliability
If hydrogen annealing is used to smooth sidewalls, then carrier mobility improves, but undercut at the bottom fin increases reducing stability
Solution Approach 1:
The patent changes the atmospheric parameters by using a controlled oxygen partial pressure environment instead of pure hydrogen atmosphere, and optimizes temperature and time parameters to achieve surface smoothing without excessive material removal at the fin bottom
Solution Approach 2:
The patent applies partial annealing action by controlling the process to smooth only the sidewall surfaces while intentionally limiting material removal at the fin bottom to maintain stability
3Reliability
If sharp corners are eliminated in fins, then subthreshold characteristics improve, but additional process steps are required increasing complexity
Solution Approach 1:
The patent merges the surface smoothing and corner rounding functions into a single integrated annealing process by controlling atmospheric composition and temperature profiles, eliminating the need for separate process steps
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 approach enhances device performance by reducing surface roughness, improving corner rounding, and stabilizing narrow fins, while broadening the thermal budget window and minimizing undercut, resulting in more efficient and reliable multi-gate devices.
Implementation Method 1
annealing and subsequently cooling down the at least one fin such that semiconductor atoms of the semiconductor material can migrate via the point defects
Implementation Method 2
creating a supersaturation of point defects in the at least one fin, then annealing and subsequently cooling down the at least one fin
Data Source
AI summary
A method for fabricating a semiconductor device and the device made thereof are disclosed. In one aspect, the method includes providing a substrate comprising a semiconductor material. The method further includes patterning at least one fin in the substrate, the fin comprising a top surface, at least one sidewall surface, and at least one corner. A supersaturation of point defects is created in the at least one fin. The at least one fin is annealed and then cooled down such that semiconductor atoms of the semiconductor material migrate via the point defects.