Semiconductor Memory Gate Spacer Formation for Ion Penetration Prevention
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Solution Overview
Problem
The semiconductor device's memory gate electrode with a smaller thickness opposite to the control gate electrode allows impurity ions to penetrate through, deteriorating the gate insulation film and affecting the performance of nonvolatile memory cells.
Innovation Solution
A manufacturing method involving the sequential formation of insulation and conductive films, with etching to create sidewall spacers and gate electrodes of varying lengths, ensuring the memory gate electrode's thickness is sufficient to prevent ion penetration and maintain film quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the memory gate electrode is formed with a smaller thickness opposite to the control gate electrode, then the operation speed and rewrite cycle of nonvolatile memory are improved, but impurity ions can penetrate through the memory gate electrode to reach the gate insulation film, deteriorating the film quality
Solution Approach 1:
A protective film is formed over the gate insulation film before forming the memory gate electrode. This protective film acts as a preliminary barrier that prevents impurity ions from penetrating through the thin memory gate electrode and reaching the gate insulation film, thus maintaining film quality while allowing the memory gate electrode to have sufficient thinness for high-speed operation
Solution Approach 2:
The protective film serves as an intermediary layer between the memory gate electrode and the gate insulation film. It mediates the interaction by blocking impurity ions from reaching the gate insulation film, thereby protecting the film quality while enabling the memory gate electrode to function at optimal thickness for speed performance
2Duration of action of moving object
If the memory gate electrode thickness is reduced to improve operation speed, then the rewrite cycle is improved, but the gate insulation film quality deteriorates due to ion penetration
Solution Approach 1:
The protective film is formed in advance over the gate insulation film before the memory gate electrode is created. This preliminary protective layer ensures that during subsequent ion implantation processes, impurity ions cannot penetrate through the thin memory gate electrode to damage the gate insulation film, thus preserving film quality while enabling fast rewrite cycles
Solution Approach 2:
The protective film acts as an intermediary barrier that decouples the relationship between memory gate electrode thickness and gate insulation film quality. It allows the memory gate electrode to be thin for fast rewrite cycles while the protective film absorbs the harmful ion penetration, maintaining gate insulation film integrity
3Ease of manufacture
If ion implantation is performed using the memory gate electrode as a mask, then the manufacturing process is simplified, but impurity ions penetrate through the thinner portion of the memory gate electrode to reach the gate insulation film
Solution Approach 1:
The protective film serves as an intermediary barrier that enables the memory gate electrode to continue functioning as an implantation mask while preventing the harmful side effect of ion penetration. The protective film blocks impurity ions from reaching the gate insulation film, thus eliminating the harmful factor while preserving the manufacturing simplicity of using the memory gate electrode as a mask
Solution Approach 2:
The protective film extracts or separates the masking function from the structural function of the memory gate electrode. The memory gate electrode maintains its masking capability for simplified manufacturing, while the protective film extracts the protective function to prevent ion penetration, thus resolving the contradiction between ease of manufacture and prevention of harmful ion penetration
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 the semiconductor device's performance by preventing impurity ion penetration and maintaining the integrity of the gate insulation film, thereby improving the reliability and operation speed of nonvolatile memory cells.
Implementation Method 1
the first film is etched back, thereby to leave the first film at the side surface of the first gate electrode via the first insulation film, the first conductive film, and the second insulation film to form a first sidewall part
Implementation Method 2
the first conductive film is etched back, thereby to form a third gate electrode formed of the first conductive film between the first sidewall part and the first gate electrode
Data Source
AI summary
The performances of a semiconductor device are improved. In a method for manufacturing a semiconductor device, a first insulation film, a conductive film, a silicon-containing second insulation film, and a third film formed of silicon are sequentially formed at the surface of a control gate electrode. Then, the third film is etched back to leave the third film at the side surface of the control gate electrode via the first insulation film, the conductive film, and the second insulation film, thereby to form a spacer. Then, the conductive film is etched back to form a memory gate electrode formed of the conductive film between the spacer and the control gate electrode, and between the spacer and the semiconductor substrate.