Mask-Programmable ROM Vertical FET Integration Process
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Solution Overview
Problem
Conventional PROM cells require data programming after manufacturing, limiting the flexibility and precision of vertical transistor technology in non-volatile memory applications, as they rely on non-vertical transistor designs.
Innovation Solution
A mask programmable read-only memory (PROM) cell is developed using a vertical transistor processing flow, where the '0' or '1' state is programmed by tuning the threshold voltage of the vertical transistor through controlled doping concentration of the epitaxially grown semiconductor channel material, allowing programming during the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional non-vertical transistor technology is used in PROM cells, then data programming can be performed after manufacturing, but the precision and scalability are limited
Solution Approach 1:
The patent applies preliminary action by programming the PROM cell data during the manufacturing process itself, rather than after manufacturing. The doping concentration of the semiconductor channel material is precisely controlled during epitaxial growth to set the threshold voltage, which permanently programs the '0' or '1' state. This eliminates the need for separate post-manufacturing programming steps and achieves both high precision and manufacturing efficiency.
Solution Approach 2:
The patent utilizes parameter changes by varying the doping concentration of the semiconductor channel material during epitaxial growth. By controlling the dopant concentration, the threshold voltage of the vertical transistor is tuned to specific values that represent binary '0' or '1' states. This parameter-based programming approach enables precise data encoding directly during manufacturing without requiring additional programming equipment or steps.
2Productivity
If vertical transistor technology is used, then scalability for 5 nm and beyond is improved, but programming during manufacturing is not achievable with conventional designs
Solution Approach 1:
The patent merges the manufacturing process with the programming function by integrating data encoding directly into the vertical transistor fabrication sequence. The epitaxial growth step simultaneously forms the semiconductor channel structure and implants the dopant concentration that determines the transistor's threshold voltage. This merging of manufacturing and programming operations achieves high productivity while maintaining the adaptability of vertical transistor technology for future scaling.
Solution Approach 2:
The patent applies preliminary action by pre-programming the PROM cell data during the manufacturing process itself. The doping concentration is precisely controlled during epitaxial growth to set the threshold voltage before the device is completed and packaged. This preliminary programming action eliminates the need for separate post-manufacturing programming steps, thereby improving manufacturing efficiency while preserving the adaptability of vertical transistor designs for advanced technology nodes.
3Loss of time
If data is programmed after manufacturing, then post-fabrication flexibility is maintained, but the process time and complexity increase
Solution Approach 1:
The patent applies preliminary action by performing the programming operation during the manufacturing process itself. The doping concentration of the semiconductor channel material is precisely controlled during epitaxial growth to establish the threshold voltage that encodes the binary data. This preliminary programming action eliminates the need for separate post-manufacturing programming steps, thereby reducing both the total process time and the overall process complexity.
Solution Approach 2:
The patent merges multiple operations into a single integrated process step. The epitaxial growth operation simultaneously forms the semiconductor channel structure, controls the doping concentration, and programs the data by setting the threshold voltage. This merging of manufacturing and programming operations reduces the total number of process steps and eliminates the time required for separate programming operations, while maintaining data flexibility through precise dopant concentration control.
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
Enables precise programming of PROM cells during the processing flow, enhancing the scalability and precision of vertical transistor technology for 5 nm and beyond, allowing for permanent data storage without post-manufacturing programming.
Implementation Method 1
a first epitaxial semiconductor channel material of a first dopant concentration extending upward from a topmost surface of the first bottom source/drain structure, and a second epitaxial semiconductor channel material of a second dopant concentration different from the first dopant concentration
Data Source
AI summary
A mask programmable read-only memory (PROM) cell is provided utilizing a vertical transistor processing flow. PROM programming is performed during the processing flow itself. Notably, “0” or “1” state can be programmed by tuning the threshold voltage of the vertical transistor by controlling the doping concentration of the epitaxially grown semiconductor channel material.