AlN MEMS Devices With Infrared Absorption Layer
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Solution Overview
Problem
Current MEMS devices for RF and low parasitics applications face challenges in achieving cost-effective solutions with efficient electrical connections and minimal parasitic effects, particularly in integrating aluminum nitride devices with infrared absorption structural layers.
Innovation Solution
The development of MEMS devices with a silicon substrate structure that includes a handle wafer with cavities, an insulating layer, a device layer bonded to the handle wafer, a metal conductive layer, and a CMOS wafer with aluminum nitride and germanium layers for eutectic bonding, enabling low parasitic connections and infrared absorption capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional MEMS devices are used for RF applications, then basic functionality is achieved, but parasitic effects increase and cost-effectiveness decreases
Solution Approach 1:
The patent employs a composite material structure consisting of a silicon substrate with an aluminum nitride structural layer deposited thereon. The aluminum nitride layer provides specific electrical and thermal properties that reduce parasitic effects in RF applications, while the silicon substrate offers mechanical strength and compatibility with standard semiconductor manufacturing processes. This composite approach enables low parasitic performance without significantly increasing manufacturing complexity.
Solution Approach 2:
The aluminum nitride structural layer serves multiple functions simultaneously: it acts as a structural support layer, provides electrical isolation to reduce parasitic capacitance, offers thermal management capabilities, and enables infrared absorption functionality. This multi-functionality reduces the need for additional separate components, thereby maintaining cost-effectiveness while addressing parasitic effects.
2Adaptability or versatility
If aluminum nitride devices with infrared absorption layers are integrated, then infrared absorption capability is achieved, but device complexity increases
Solution Approach 1:
The patent merges the infrared absorption functionality directly into the existing MEMS device structure by depositing the aluminum nitride structural layer that inherently provides infrared absorption capabilities. This integration approach combines multiple functions (structural support, electrical isolation, and infrared absorption) into a single layered component, avoiding the need for separate infrared absorption elements and thereby limiting the increase in device complexity.
Solution Approach 2:
The aluminum nitride layer's material properties are optimized to provide infrared absorption capability through controlled deposition parameters such as thickness, density, and crystalline structure. By adjusting these parameters during the deposition process, the layer achieves desired infrared absorption characteristics while maintaining compatibility with standard MEMS fabrication processes, thus limiting complexity increases.
3Reliability
If eutectic bonding with aluminum and germanium layers is used, then electrical connection quality is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes the eutectic phase transition phenomenon between aluminum and germanium layers to achieve reliable electrical connections. During the bonding process, the aluminum and germanium layers are heated to their eutectic temperature, causing a phase transition that enables intimate metallurgical bonding. This phase transition mechanism provides self-aligning and self-correcting properties that compensate for minor misalignments, thereby improving electrical connection quality while moderating the impact of manufacturing precision variations.
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 enhances the electrical connections and reduces parasitic effects, making the MEMS devices more suitable for RF and low parasitics applications while incorporating aluminum nitride for infrared absorption, thus improving their performance and efficiency.
Implementation Method 1
The one or more stand-offs is bonded to the one or more aluminum pads utilizing eutectic point between the one or more aluminum pads and the germanium layer
Implementation Method 2
aluminum nitride for infrared absorption
Data Source
AI summary
A micro-electro-mechanical system device is disclosed. The micro-mechanical system device comprises a first silicon substrate comprising: a handle layer comprising a first surface and a second surface, the second surface comprises a cavity; an insulating layer deposited over the second surface of the handle layer; a device layer having a third surface bonded to the insulating layer and a fourth surface; a piezoelectric layer deposited over the fourth surface of the device layer; a metal conductivity layer disposed over the piezoelectric layer; a bond layer disposed over a portion of the metal conductivity layer; and a stand-off formed on the first silicon substrate; wherein the first silicon substrate is bonded to a second silicon substrate, comprising: a metal electrode configured to form an electrical connection between the metal conductivity layer formed on the first silicon substrate and the second silicon substrate.