Gate Spacer Layout for I/O Transistors Under Hot Carrier Stress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The scaling down of semiconductor devices leads to increased electric fields in gate dielectric layers, causing hot carrier injection (HCI), which degrades device performance and results in leakages, especially in input/output (I/O) devices operating at higher voltages than core devices.
Innovation Solution
Implementing different gate spacer arrangements for I/O and core devices on the same substrate, where I/O devices include an additional booster spacer made of silicon oxide, protected by etch-resistant spacers, to increase the distance between the channel and drain, reducing HCI occurrences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gate dielectric layer thickness is reduced to enable device scaling, then device production efficiency increases and costs decrease, but electric fields in the gate dielectric layer increase causing hot carrier injection and device degradation
Solution Approach 1:
The patent applies different spacer configurations to different device regions: I/O devices receive an additional thicker spacer (totaling 10-20 nm) while core devices use standard spacers. This local differentiation allows I/O devices to have reduced electric fields and suppressed HCI without impacting core device performance or production efficiency.
2Reliability
If supply voltage is reduced to match scaled device requirements, then device reliability improves, but the pace of voltage reduction lags behind device scaling causing increased electric fields
Solution Approach 1:
The patent segments the substrate into I/O device regions and core device regions, applying different spacer structures to each. I/O devices receive enhanced spacers to compensate for higher operating voltages, while core devices use standard spacers. This segmentation allows each region to be optimized independently for its specific voltage and performance requirements.
3Adaptability or versatility
If I/O devices operate at higher voltages to interface external circuitry, then external interface capability is maintained, but hot carrier injection increases degrading device performance
Solution Approach 1:
The patent applies preliminary protective measures by forming thicker spacers around I/O device gates before the HCI damage occurs. These spacers pre-establish electric field shielding that prevents hot carriers from injecting into the gate dielectric, thereby protecting I/O devices from HCI degradation while maintaining their high-voltage external interface capability.
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 reduces HCI-related failures and performance issues in I/O devices by maintaining the switching speed requirements for core devices while minimizing hot carrier injection, thus enhancing the reliability and efficiency of semiconductor devices.
Implementation Method 1
protected by etch-resistant spacers
Data Source
AI summary
Semiconductor devices and methods are provided. A semiconductor device according to the present disclosure includes a first transistor in a first area and a second transistor in a second area. The first transistor includes a first gate structure extending lengthwise along a first direction, and a first gate spacer, a second gate spacer, and a third gate spacer over sidewalls of the first gate structure. The second transistor includes a second gate structure extending lengthwise along the first direction, and the first gate spacer and the third gate spacer over sidewalls of the second gate structure. The first gate spacer, the second gate spacer and the third gate spacer are of different compositions and the third gate spacer is directly on the first gate spacer in the second area.