Titanium Silicide Formation via Cyclic Precursor Deposition
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Solution Overview
Problem
Conventional methods for forming titanium silicide in high-aspect-ratio openings face challenges such as agglomeration and incomplete phase transformation from high resistivity C-49 to low resistivity C-54, especially in semiconductor applications, where achieving low resistive contacts is difficult due to these issues.
Innovation Solution
A method involving alternating cycles of titanium halide precursor and activated hydrogen in a deposition process to form low resistivity TiSi2 (C-54 phase) at low temperatures, selectively forming titanium silicide on silicon-containing surfaces while avoiding post-annealing, using titanium tetrachloride and hydrogen plasma to control the growth and conversion of titanium halide layers into titanium silicide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PVD or CVD techniques are used to form titanium films, then deposition can be achieved, but complete phase transformation from C-49 to C-54 cannot be achieved and agglomeration occurs in high-aspect-ratio openings
Solution Approach 1:
The deposition process is segmented into alternating cycles: titanium halide precursor exposure forms a thin layer, then activated hydrogen exposure converts it to titanium silicide. This cyclic segmentation allows controlled phase transformation without agglomeration by processing thin layers iteratively rather than forming thick layers in one step.
Solution Approach 2:
The patent employs periodic alternating exposure to titanium halide precursor and activated hydrogen in cyclic pulses. This periodic action enables repeated formation and conversion of thin titanium silicide layers, ensuring complete C-49 to C-54 phase transformation while preventing agglomeration through controlled incremental growth.
2Reliability
If post-deposition annealing is used to convert C-49 to C-54 phase, then phase transformation can occur, but excessive processing time and temperature are required
Solution Approach 1:
The titanium halide precursor is deposited in a controlled manner before conversion to titanium silicide. This preliminary formation of the correct stoichiometry through alternating deposition cycles prepares the material in advance for low-temperature C-54 phase formation, eliminating the need for subsequent high-temperature annealing processes.
Solution Approach 2:
The patent changes the deposition parameters by using titanium halide precursors with activated hydrogen to directly form C-54 phase at lower temperatures (500-700°C). This parameter change in the chemical deposition process enables phase transformation without requiring traditional high-temperature annealing, reducing processing time significantly.
3Quantity of substance
If conventional deposition methods are used, then titanium films can be formed, but excessive silicon consumption occurs
Solution Approach 1:
Titanium halide precursor serves as an intermediary that reacts with silicon to form titanium silicide. The halide group facilitates controlled reaction with silicon, enabling precise stoichiometry control and reducing excessive silicon consumption compared to direct titanium deposition 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 method enables the direct formation of the C-54 phase of titanium silicide with improved selectivity and reduced agglomeration, allowing for the formation of low resistivity contacts at the bottom of high-aspect-ratio openings without the need for post-deposition annealing, enhancing semiconductor processing efficiency.
Implementation Method 1
Titanium from the titanium-containing layer is reacted with semiconductor material of the substrate to form the desired titanium-containing material
Implementation Method 2
utilizing alternating cycles of titanium halide precursor (such as, for example, titanium tetrachloride (TiCl4)) and activated hydrogen (such as, for example, hydrogen from a H2 plasma)
Data Source
AI summary
The invention includes methods of forming titanium-containing materials, such as, for example, titanium silicide. The invention can use alternating cycles of titanium halide precursor and one or more reductants to form the titanium-containing material. For instance, the invention can utilize alternating cycles of titanium tetrachloride and activated hydrogen to form titanium silicide on a surface of a silicon-containing substrate.