Multi-threshold Voltage IC Using Selective Gate Work Functions
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Solution Overview
Problem
Current methods for fabricating multi-threshold voltage IC devices face challenges such as mobility degradation, junction leakage, and increased costs due to heavier implantation processes and the need for separate masks for each threshold voltage, while also consuming valuable space as technology nodes shrink.
Innovation Solution
The method involves using gate materials with different work function types to achieve various threshold voltage characteristics, allowing for the same channel type devices to be configured with fewer and lighter implantation processes, reducing the need for multiple masks and conserving device area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate masks are used for each desired threshold voltage, then different threshold voltage devices are achieved, but manufacturing cost increases
Solution Approach 1:
The patent uses a single mask pattern that defines all device regions, and then selectively deposits different gate electrode materials in different regions. This universal masking approach eliminates the need for separate masks for each threshold voltage device type, reducing manufacturing complexity and cost while maintaining the ability to produce multiple threshold voltage variants.
Solution Approach 2:
The patent segments the gate electrode deposition process into region-specific material deposition steps after a single mask application. Different gate materials are deposited in different device regions through selective area deposition techniques, allowing multiple threshold voltage characteristics to be achieved from one mask pattern rather than requiring separate masks for each segment.
2Reliability
If channel length is enlarged to accommodate higher threshold voltage devices, then threshold voltage is improved, but device space is consumed
Solution Approach 1:
The patent changes the gate electrode material parameter (work function) to control threshold voltage instead of changing the geometric parameter (channel length). This allows threshold voltage adjustment without increasing device footprint, maintaining high functional density while achieving the required voltage characteristics through material selection rather than geometric scaling.
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 device performance by reducing mobility degradation and junction leakage, saving space and costs, while enabling more devices to be fabricated in a smaller area without enlarging channel lengths, thus improving overall device reliability and efficiency.
Implementation Method 1
the first gate including a first material having a first-type work function; forming a second gate over the substrate for a second device having a second threshold voltage characteristic that is greater than the first threshold voltage characteristic, the second gate including a second material having a second-type work function that is opposite the first-type work function
Data Source
AI summary
An integrated circuit device and method for manufacturing the integrated circuit device are disclosed. An exemplary method includes providing a substrate; forming a first gate over the substrate for a first device having a first threshold voltage characteristic, the first gate including a first material having a first-type work function; forming a second gate over the substrate for a second device having a second threshold voltage characteristic that is greater than the first threshold voltage characteristic, the second gate including a second material having a second-type work function that is opposite the first-type work function; and configuring the first device and the second device as a same channel type device.