Blocking Semiconductor Layer Suppresses Boron Penetration
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Solution Overview
Problem
Implant species, such as boron, penetrate into the floating gates of semiconductor devices, causing threshold voltage shifts and reducing device reliability, necessitating a solution to suppress their penetration.
Innovation Solution
A semiconductor device is designed with a blocking semiconductor layer and a polysilicon layer, where the blocking semiconductor layer has a specific dopant concentration and grain size range, minimizing the penetration of implant species into the polysilicon layers by creating an interface that restricts diffusion, particularly effective for small atomic weight elements like boron.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If implant species are used as dopants in semiconductor devices, then device functionality is achieved, but implant species penetrate into floating gates causing threshold voltage shifts and reliability issues
Solution Approach 1:
A blocking semiconductor layer is introduced as an intermediary between the implant species source and the floating gate. This layer acts as a mediator that allows the implantation process to proceed while preventing harmful species from reaching the floating gate, thus resolving the contradiction between achieving device functionality and preventing harmful penetration.
Solution Approach 2:
The semiconductor structure is segmented into multiple layers with distinct functions: a blocking semiconductor layer with specific dopant concentrations and grain sizes is separated from the floating gate. This segmentation creates a barrier zone that stops implant species while allowing the floating gate to maintain its electrical function.
2Object-affected harmful factors
If a blocking semiconductor layer with specific dopant concentration and grain size is introduced, then implant species penetration is suppressed, but device structure complexity increases
Solution Approach 1:
The blocking semiconductor layer is created by modifying parameters of an existing semiconductor layer - specifically adjusting dopant concentration (first dopant in first concentration versus first dopant in second concentration) and grain size. These parameter changes transform a standard semiconductor layer into a functional blocking layer without requiring entirely new materials or complex multi-layer structures.
Solution Approach 2:
The blocking semiconductor layer functions as a composite structure combining semiconductor material with specific dopant profiles and controlled grain sizes. This composite approach creates a material with enhanced blocking properties while maintaining compatibility with standard semiconductor fabrication processes.
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
The solution effectively minimizes boron penetration into the floating gate, preventing unwanted threshold voltage shifts and enhancing the reliability of semiconductor devices by using a blocking semiconductor layer with controlled dopant concentrations and grain sizes to restrict implant species diffusion.
Implementation Method 1
minimizing the penetration of implant species into the polysilicon layers by creating an interface that restricts diffusion
Implementation Method 2
The first polysilicon layer may including the first dopant in a second concentration, and the first concentration is less than the second concentration
Data Source
AI summary
A blocking semiconductor layer minimizes penetration of implant species into a semiconductor layer beneath the blocking semiconductor layer. The blocking semiconductor layer may have grains with relatively fine or small grain sizes and/or may have a dopant in a relatively low concentration to minimize penetration of implant species into the semiconductor layer beneath the blocking semiconductor layer.