Integrated Power Amplifier and Acoustic Wave Device on Compound Semiconductor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional acoustic wave devices on silicon substrates face challenges with component size reduction, impedance matching, and signal loss when integrated with power amplifiers, and require costly and time-consuming chemical mechanical polishing, which also limits the design's ability to widen the gap between the acoustic wave device and the recess, leading to potential stress-induced bending issues.
Innovation Solution
An integrated structure of power amplifier and acoustic wave device on a compound semiconductor epitaxial substrate, featuring a film bulk acoustic resonator with a supporting layer and optimized recess design to increase the gap between the supporting layer mesa and the substrate recess, reducing contact and signal loss, and utilizing a heterojunction bipolar transistor or field effect transistor configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical mechanical polishing (CMP) is used to remove the phosphosilicate glass layer outside the recess, then the surface roughness can be made smooth enough for acoustic wave device formation, but the production cost and time consumption increase significantly
Solution Approach 1:
The invention extracts and removes the phosphosilicate glass layer selectively from the recess area using chemical etching, while leaving the layer intact outside the recess. This eliminates the need for CMP processing to achieve smooth surfaces, as the acoustic wave device is formed only within the recess where the glass layer is removed. The solution resolves the contradiction by extracting only the necessary portion of the glass layer rather than polishing the entire surface.
Solution Approach 2:
The invention uses a sacrificial phosphosilicate glass layer that is intentionally deposited and then selectively removed by chemical etching. This disposable layer serves as a temporary structure during fabrication, enabling simple recess formation without requiring expensive CMP equipment. The glass layer is discarded after serving its purpose, replacing the need for costly and time-consuming polishing processes.
2Device complexity
If a single recess design is used for the acoustic wave device, then the structure is simple, but the gap between the bottom of the acoustic wave device and the bottom of the recess cannot be efficiently widened, causing stress-induced bending issues
Solution Approach 1:
The invention segments the single recess into multiple recesses (first recess and second recess) with different depths. The first recess has a greater depth than the second recess, creating a stepped structure. This segmentation allows the acoustic wave device to be positioned at an optimal height, efficiently widening the gap between the device bottom and the deepest recess bottom. The segmented design prevents stress-induced bending while maintaining structural simplicity through a systematic multi-level approach.
Solution Approach 2:
The invention introduces a depth dimension variation by creating recesses at different depths rather than using a uniform single-depth recess. The first recess extends deeper into the substrate than the second recess, creating a vertical dimensional hierarchy. This dimensional change enables optimal positioning of the acoustic wave device, widening the protective gap without adding horizontal complexity, thus resolving the contradiction between structural simplicity and stress resistance.
3Area of stationary object
If acoustic wave device and power amplifier are integrated on the same compound semiconductor epitaxial substrate, then the component size is reduced and impedance matching is optimized, but the manufacturing process complexity increases
Solution Approach 1:
The invention merges the acoustic wave device and power amplifier onto the same compound semiconductor epitaxial substrate, integrating two previously separate components into a single unified structure. The acoustic wave device is formed in a first recess while the power amplifier is formed in a second recess on the same substrate. This merging reduces overall component size and optimizes impedance matching between the devices while maintaining manufacturability through standardized semiconductor fabrication processes.
Solution Approach 2:
The invention applies local quality by creating different recess depth configurations for different functional areas. The first recess for the acoustic wave device has a greater depth than the second recess for the power amplifier. This localized differentiation optimizes each component's performance independently - the deeper first recess provides stress relief for the acoustic wave device, while the shallower second recess is suitable for the power amplifier - without complicating the overall integration process.
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 reduces component size, optimizes impedance matching, and minimizes signal loss between the power amplifier and acoustic wave device, while avoiding stress-induced bending and reducing production costs by eliminating the need for expensive and time-consuming polishing processes.
Implementation Method 1
film bulk acoustic resonator (51)... bulk acoustic resonator structure (60)... acoustic wave device
Data Source
AI summary
An integrated structure of power amplifier and acoustic wave device comprises: a compound semiconductor epitaxial substrate including an epitaxial structure formed on a compound semiconductor substrate, a power amplifier upper structure formed on a top-side of a left part of the compound semiconductor epitaxial substrate, and a film bulk acoustic resonator formed on the top-side of a right part of the compound semiconductor epitaxial substrate; wherein the left part of the compound semiconductor epitaxial substrate and the power amplifier upper structure form a power amplifier; the right part of the compound semiconductor epitaxial substrate and the film bulk acoustic resonator form an acoustic wave device; the integrated structure of power amplifier and acoustic wave device on the same compound semiconductor epitaxial substrate is capable of reducing the component size, optimizing the impedance matching, and reducing the signal loss between power amplifier and acoustic wave device.