TiN Buffer Film Adhesion for SiC MOSFET Source Electrodes
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Solution Overview
Problem
In MOSFET devices, insufficient adhesion between the aluminum source electrode and the interlayer insulating film leads to device characteristic instability, as the source electrode may detach, affecting the overall performance.
Innovation Solution
A semiconductor device structure incorporating a substrate made of silicon carbide with a gate insulating film, a gate electrode, an interlayer insulating film, a buffer film containing Ti and N (with no Al), and a source electrode composed of Ti, Al, and Si, where the buffer film is formed on the side wall surface of a contact hole extending through the interlayer insulating film to enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a source electrode containing aluminum is formed to contact the interlayer insulating film, then electrical connection is achieved, but adhesion between the source electrode and interlayer insulating film is insufficient causing the source electrode to come off
Solution Approach 1:
A buffer film containing Ti and N (TiN) is introduced as an intermediary layer between the aluminum source electrode and the interlayer insulating film. This buffer film serves as a mediator that enhances adhesion by providing compatible bonding interfaces with both the aluminum electrode and the insulating film, preventing direct contact that would otherwise result in insufficient adhesion and electrode detachment.
Solution Approach 2:
The source electrode structure is transformed from a simple aluminum layer to a composite structure consisting of multiple layers: the aluminum source electrode, the TiN buffer film, and the interlayer insulating film. This composite material approach combines materials with complementary properties to achieve both electrical conductivity (from Al) and strong adhesion (from TiN buffer film)
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 configuration improves the adhesion between the source electrode and the interlayer insulating film, resulting in a semiconductor device with stable characteristics by ensuring the source electrode remains securely attached, thereby enhancing the device's operational stability.
Implementation Method 1
improving adhesion between the source electrode and the interlayer insulating film
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A MOSFET (1) includes: a substrate (10); a gate insulating film (20); a gate electrode (30); an interlayer insulating film (40) formed on the gate insulating film (20) to surround the gate electrode (30); a buffer film (51) containing Ti and N and containing no Al; and a source electrode (52) containing Ti, Al, and Si. In the MOSFET (1), a contact hole (80) is formed away from the gate electrode (30) so as to extend through the interlayer insulating film (40) and expose a main surface (10A) of the substrate (10). The buffer film (51) is formed in contact with a side wall surface (80A) of the contact hole (80). The source electrode (52) is formed on and in contact with the buffer film (51) and the main surface (10A) of the substrate (10) exposed by forming the contact hole (80).