AlN-Based MIM Capacitor for High Breakdown Voltage
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Solution Overview
Problem
Conventional metal insulator metal (MIM) capacitors using silicon nitride films in nitride semiconductor devices face a trade-off between breakdown voltage and capacitance, where increasing breakdown voltage requires enlarging the chip area, and achieving sufficient capacitance and voltage simultaneously is challenging.
Innovation Solution
A semiconductor device is designed with a laminated structure of AlN, GaN, and AlGaN layers on a semiconductor substrate, featuring specific openings and electrodes to form a MIM capacitor, utilizing the AlN layer as the insulating film, which enhances breakdown voltage without increasing chip area by leveraging the higher band gap energy and dielectric constant of AlN.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the SiNx film is thickened to increase breakdown voltage, then the withstand voltage is improved, but the capacitance is reduced proportionally and chip area must be enlarged
Solution Approach 1:
The patent changes the material parameter of the insulating film from SiNx to AlN, which has fundamentally different electrical characteristics including higher breakdown field strength and higher dielectric constant. This material parameter change allows achieving both high breakdown voltage and sufficient capacitance without increasing chip area
Solution Approach 2:
The patent uses a composite structure combining AlN insulating film with metal electrodes (such as Ti/Al/Ni/Au) to form a MIM capacitor with optimized performance. The combination of AlN's high breakdown field and high dielectric constant with appropriate metal electrodes creates a capacitor that simultaneously achieves high withstand voltage and sufficient capacitance
2Reliability
If the SiNx film is thickened to increase breakdown voltage, then the withstand voltage is improved, but the chip area must be enlarged to maintain capacitance
Solution Approach 1:
The patent changes the material parameter of the insulating film from SiNx to AlN, which has fundamentally different electrical characteristics including higher breakdown field strength and higher dielectric constant. This material parameter change allows achieving both high breakdown voltage and sufficient capacitance without increasing chip area
Solution Approach 2:
The patent transitions from the conventional SiNx-based capacitor design to an AlN-based MIM capacitor structure, representing a dimensional change in the material system. This allows exploiting the unique properties of AlN (high breakdown field and high dielectric constant) to achieve superior performance in the same physical space
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 ensures sufficient capacitance and breakdown voltage, achieving a breakdown voltage of approximately 190 V while maintaining a compact chip area, outperforming conventional SiNx film capacitors.
Implementation Method 1
an insulating film which is different from a silicon nitride (SiNx) film is used, a breakdown voltage of approximately 190 V can be achieved
Implementation Method 2
ensures sufficient capacitance and withstand voltage
Data Source
AI summary
A semiconductor device comprises an AlN layer, a GaN layer, and an AlGaN layer sequentially formed on a semiconductor substrate. A first opening extends through said GaN layer and said AlGaN layer and exposes part of an upper surface of the AlN layer. A second opening extends through the semiconductor substrate and exposes a part of a lower surface of the AlN layer, in a location facing the first opening. A upper electrode is exposed on an upper surface of the AlN layer in the first opening; and a lower electrode is disposed on a lower surface of the AlN layer in the second opening.