Silicon Nitride ALD Doping for 3D NAND Charge Retention
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Solution Overview
Problem
Existing methods for forming silicon nitride films doped with metals, such as aluminum, face challenges in accurately controlling the doping amount, leading to trade-offs in charge write/erase characteristics and charge retention, which are critical for high-density charge trapping in 3D NAND memory applications.
Innovation Solution
A film deposition method involving a thermal atomic layer deposition process that alternately supplies silicon-containing, metal-containing, and nitrogen-containing gases into a processing chamber, allowing for precise control of metal doping by varying the sequence and frequency of gas supply, thereby forming silicon nitride films with tailored aluminum doping levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metal-containing gas is supplied continuously during silicon nitride film deposition, then metal doping amount increases, but charge retention characteristic deteriorates
Solution Approach 1:
The patent applies periodic action by alternately supplying silicon-containing gas and metal-containing gas in cyclic sequences. The metal-containing gas is supplied only during specific cycles (not all cycles), creating a periodic doping pattern that controls the average metal concentration in the film. This periodic supply method enables precise control of metal doping amount while maintaining charge retention characteristics by limiting metal exposure to specific time windows during deposition.
Solution Approach 2:
The patent utilizes parameter changes by varying the supply frequency and duration of metal-containing gas relative to silicon-containing gas. By adjusting the ratio of cycles with metal supply to total cycles, and controlling the supply time within each cycle, the metal doping concentration can be precisely tuned. This parameter control allows optimization of both metal doping amount and charge retention characteristic.
2Manufacturing precision
If conventional metal doping method is used, then doping amount control precision is insufficient, but process complexity increases with alternative methods
Solution Approach 1:
The patent achieves high doping amount control precision through periodic action while maintaining relatively simple process structure. By using cyclic alternation of silicon-containing gas and metal-containing gas supply, the method precisely controls metal incorporation without requiring complex additional equipment or processes. The periodic pattern is controlled through standard deposition cycle management.
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 stable and precise adjustment of aluminum doping in silicon nitride films, enhancing charge retention characteristics and allowing for optimized charge writing performance in 3D NAND memory applications.
Implementation Method 1
a film deposition method involving a thermal atomic layer deposition process that alternately supplies silicon-containing, metal-containing, and nitrogen-containing gases into a processing chamber
Data Source
AI summary
With respect to a film deposition method of depositing a silicon nitride film doped with a desired metal on a substrate, the film deposition method includes (a) supplying a silicon-containing gas into a processing chamber in which the substrate is accommodated, (b) supplying a metal-containing gas into the processing chamber, the metal-containing gas containing the desired metal, (c) supplying a nitrogen-containing gas into the processing chamber, after performing (a) at least once and performing (b) at least once.