In-Situ Steam Oxynitride Growth for Faster Gate Oxide Processing
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Solution Overview
Problem
Existing semiconductor gate structures require post-oxidation annealing and decoupled plasma nitridation to achieve necessary electrical specifications for oxide layers, which increases processing time and complexity, and do not inherently introduce nitrogen effectively.
Innovation Solution
The in-situ steam generation (ISSG) process forms an oxide layer using a gas mixture of H2, O2, and N2O in a rapid thermal process chamber, allowing for nitrogen introduction without separate processes like DPN, with adjustable flow rates and temperatures to improve electrical properties and reduce processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ISSG process is used to form oxide layer, then oxidation is achieved, but post-oxidation annealing is required to improve electrical properties
Solution Approach 1:
The patent combines the oxidation process with nitrogen introduction into a single integrated process step. By introducing nitrogen-containing gas (such as NH3 or N2) during the ISSG oxidation process, the oxide layer is formed with incorporated nitrogen, eliminating the need for separate post-oxidation annealing and decoupled plasma nitridation steps. This merging of processes reduces total processing time while maintaining or improving electrical properties.
Solution Approach 2:
The patent performs nitrogen introduction during the oxidation process itself, rather than as a subsequent step. By incorporating nitrogen into the oxide layer during formation, the electrical properties are improved in advance, eliminating the need for later annealing treatments to achieve the necessary electrical specifications.
2Quantity of substance
If decoupled plasma nitridation is used to introduce nitrogen, then nitrogen is incorporated into oxide layer, but separate process step increases complexity
Solution Approach 1:
The patent merges the nitrogen introduction function with the oxidation process by introducing nitrogen-containing gases (such as NH3, N2, or N2O) during the ISSG oxidation. This integration eliminates the need for a separate decoupled plasma nitridation process, reducing equipment complexity and process steps while achieving the required nitrogen content in the oxide layer for boron penetration reduction.
Solution Approach 2:
The oxidation process is given multiple functions: it simultaneously oxidizes the silicon substrate to form the oxide layer and introduces nitrogen into the layer. This multi-functionality is achieved by controlling the gas composition (adding nitrogen-containing components to the H2/O2 mixture) and process parameters during ISSG, making the oxidation step universally perform both oxidation and nitridation functions.
3Reliability
If multiple separate processes are used (ISSG + POA + DPN), then electrical specifications are met, but processing time increases
Solution Approach 1:
The patent consolidates three separate processes (ISSG oxidation, POA annealing, and DPN nitridation) into a single integrated ISSG process with modified gas composition. By introducing nitrogen-containing gases during oxidation and controlling process parameters (temperature, gas flow rates, pressure), the method simultaneously achieves oxide formation, nitrogen incorporation, and electrical property improvement in one continuous step, reducing total processing time while meeting all electrical specifications.
Solution Approach 2:
The patent maintains continuous useful action by performing oxidation and nitrogen introduction simultaneously in a single continuous process without intermediate annealing or separate treatment steps. The ISSG process runs continuously with optimized gas composition and parameters, ensuring that the oxide layer is formed with the required nitrogen content and electrical properties in one uninterrupted operation, maximizing process efficiency and minimizing time loss.
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 forms oxide layers with improved electrical properties, such as reduced gate oxide breakdown and interface trap density, without the need for post-oxidation annealing, while integrating nitrogen directly into the oxide layer, thus simplifying the process and meeting electrical specifications.
Implementation Method 1
pre-mixed H2 and O2 are introduced into a rapid thermal process (RTP) chamber. The gas mixture flows across a rotating wafer heated by tungsten-halogen lamps. The hot wafer ignites the reaction between H2 and O2 close to the wafer to form steam
Implementation Method 2
The hot wafer ignites the reaction between H2 and O2 close to the wafer to form steam and thereby oxidize the wafer
Data Source
AI summary
A method of forming an oxide layer in an in-situ steam generation (ISSG) process, including providing a silicon substrate in a rapid thermal process (RTP) chamber and injecting a gas mixture into the RTP chamber. The method further includes heating a surface of the silicon substrate to a reaction temperature, so that the gas mixture reacts close to the surface to form steam and thereby oxidize the silicon substrate to form the oxide layer on the surface, and wherein the gas mixture comprises hydrogen (H2), oxygen (O2) and nitrous oxide (N2O).