Threshold Voltage Tuning Layer Deposition for Precise Work Function Control
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Solution Overview
Problem
Conventional methods for forming threshold voltage tuning layers in semiconductor devices face challenges in controlling the initial thickness and deposition rate, especially as device dimensions continue to shrink, requiring improved techniques for achieving desired work function values and resistivity tuning.
Innovation Solution
The method involves treating a substrate surface with metal or carbon-containing precursors to control the deposition rate of threshold voltage tuning material, using cyclical deposition processes and etchants to achieve a desired thickness and properties, such as silicon-doped niobium oxide or aluminum oxide layers, for applications in CMOS devices and MOSFETs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods are used to form threshold voltage tuning layers, then the deposition process is simple and fast, but the initial thickness and deposition rate are difficult to control
Solution Approach 1:
The deposition process is segmented into multiple cycles, where each cycle deposits a portion of the threshold voltage tuning layer. By controlling the number of cycles and deposition parameters for each cycle, precise thickness control is achieved while managing process complexity through systematic breakdown of the deposition task
Solution Approach 2:
Surface treatment is performed as a preliminary action before deposition to modify the substrate surface properties. This preliminary treatment establishes controlled nucleation conditions that regulate the initial deposition rate and thickness uniformity, enabling precise thickness control from the start of the deposition process
2Manufacturing precision
If the threshold voltage tuning layer thickness is increased to achieve desired work function values, then work function tuning is improved, but the initial deposition rate becomes uncontrolled and excessive
Solution Approach 1:
The deposition process uses dynamic parameter adjustment where deposition conditions (such as precursor flow rates, temperature, or pressure) are modified during the deposition cycles. This dynamic control enables the deposition rate to be adjusted in real-time, achieving precise thickness control while maintaining productivity by optimizing the overall deposition timeline
Solution Approach 2:
The deposition is performed through periodic cycles rather than continuous deposition. Each cycle allows for controlled material addition with reset conditions, enabling precise control over the cumulative thickness while maintaining high productivity through efficient cycle timing and parameter optimization
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 allows for precise control of the growth rate and properties of threshold voltage tuning layers, enhancing work function tuning, stress management, and resistivity tuning, making them suitable for gate electrodes in advanced semiconductor devices.
Implementation Method 1
treating a surface of a substrate to control a deposition rate of a subsequently deposited threshold voltage shifting layer
Implementation Method 2
depositing threshold voltage tuning material overlying the treated surface
Implementation Method 3
the step of depositing threshold voltage tuning material comprises a cyclical deposition process
Implementation Method 4
the threshold voltage tuning material reactant can remove a ligand of the treatment reactant on the treated surface
Data Source
AI summary
Methods and systems for forming structure comprising a threshold voltage tuning layer are disclosed. Exemplary methods include providing a treatment reactant to a reaction chamber to form a treated surface on the substrate surface and depositing threshold voltage tuning material overlying the treated surface. Additionally or alternatively, exemplary methods can include direct formation of metal silicide layers. Additionally or alternatively, exemplary methods can include use of an etchant.