Fluorine Ion Implantation for Semiconductor Gate Stability
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Solution Overview
Problem
Current semiconductor technologies face issues with negative bias temperature instability (NBTI) due to electrical instability in gate structures, particularly in CMOS devices with PMOS structures, caused by boron penetration and depletion effects, which affect the performance and reliability of devices.
Innovation Solution
A method involving ion implantation of fluorine ions at a tilted angle into the substrate and gate structure to form a layered interface with varying fluorine concentrations, enhancing the bond strength between material layers and reducing NBTI effects by creating Si—F bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If work function materials are used in gate structures, then electrical performance is improved, but electrical instability and NBTI effect occur
Solution Approach 1:
An interface layer is introduced as an intermediary between the substrate and the gate structure. This interface layer, formed by fluorine ion implantation, acts as a mediator that prevents direct interaction between the work function material and the substrate, thereby eliminating the NBTI effect while preserving the electrical performance benefits of work function materials.
Solution Approach 2:
The interface layer modifies the chemical and physical parameters at the substrate-gate interface by introducing fluorine atoms that form Si-F bonds. This parameter change in the interface composition stabilizes the electrical properties and prevents the accumulation of electrical potentials that cause NBTI effect.
2Strength
If fluorine ions are implanted at high concentration, then bond strength is improved, but manufacturing complexity increases
Solution Approach 1:
The fluorine ion implantation is performed as a preliminary action before forming the gate structure. By pre-forming the interface layer with the required fluorine concentration profile, the subsequent gate fabrication steps are simplified, and the overall manufacturing complexity is reduced despite the additional implantation step.
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 method improves the stability and performance of semiconductor devices by increasing the bond strength between material layers, thereby reducing NBTI-induced electrical instability and enhancing the overall reliability of the devices.
Implementation Method 1
performing a first implantation process for implanting fluorine ions at a tiled angle into the substrate and part of the gate structure
Implementation Method 2
enhancing the bond strength between material layers and reducing NBTI effects by creating Si—F bonds
Data Source
AI summary
A method for fabricating semiconductor device is disclosed. The method includes the steps of: providing a substrate; forming a gate structure on the substrate; forming a lightly doped drain in the substrate; and performing a first implantation process for implanting fluorine ions at a tiled angle into the substrate and part of the gate structure.