Dielectric Platform with Voids for RF Isolation
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Solution Overview
Problem
Semiconductor devices, particularly in high-frequency or RF applications, face challenges with low quality factors and reduced operational frequencies due to parasitic capacitive coupling with conductive substrates, necessitating the development of structures that minimize parasitic capacitances and enhance isolation.
Innovation Solution
A semiconductor structure incorporating a dielectric platform with high aspect ratio voids and dielectric materials, fabricated using electrochemical etching, which reduces the dielectric constant and parasitic capacitance, thereby increasing operational frequency and breakdown voltage while providing electrical isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If passive devices are formed on or in close proximity to a conductive substrate, then device integration is achieved, but parasitic capacitive coupling increases causing reduced quality factors and lower operational frequencies
Solution Approach 1:
A dielectric platform is introduced as an intermediary layer between the conductive substrate and the passive devices (inductors, capacitors, interconnects). This dielectric platform with high aspect ratio voids acts as a mediator that reduces parasitic capacitive coupling while allowing the passive devices to remain integrated over the substrate, thus resolving the contradiction between integration and parasitic coupling reduction.
Solution Approach 2:
The dielectric platform incorporates high aspect ratio voids (porous structure) that reduce the effective dielectric constant of the platform. This porous structure decreases the parasitic capacitance between passive devices and the conductive substrate, improving quality factors and operational frequencies while maintaining the integrated device configuration.
2Reliability
If a solid dielectric structure is used to reduce parasitic capacitance, then isolation is improved, but the dielectric constant remains high reducing effectiveness
Solution Approach 1:
High aspect ratio voids are formed within the dielectric platform, creating a porous structure that reduces the effective dielectric constant. The voids occupy significant volume within the dielectric platform, lowering the average permittivity and thereby reducing parasitic capacitance while maintaining electrical isolation functionality.
Solution Approach 2:
The dielectric platform is formed as a composite structure combining dielectric material with void spaces. This composite architecture achieves an effective dielectric constant lower than the base dielectric material alone, improving parasitic capacitance reduction while maintaining structural integrity and electrical isolation.
3Power
If power transistors are designed for high output power with increased breakdown voltage, then output power capability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The dielectric platform serves as an intermediary structure that enables high breakdown voltage operation by providing enhanced electrical isolation and reducing parasitic effects. This allows power transistors to achieve higher output power capabilities without proportionally increasing device complexity, as the dielectric platform provides the necessary electrical environment for high voltage operation.
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 dielectric platform effectively reduces parasitic capacitance, increases operational frequency, and enhances the quality factor of passive devices, enabling higher breakdown voltages and improved isolation in semiconductor structures.
Implementation Method 1
fabricated using electrochemical etching
Data Source
AI summary
In various embodiments, semiconductor structures and methods to manufacture these structures are disclosed. In one embodiment, a method includes removing a portion of a semiconductor material using an electrochemical etch to form a first cavity, a second cavity, wherein the first cavity is isolated from the second cavity, a first protrusion is between the first cavity and the second cavity, and the semiconductor material comprises silicon. The method further includes performing a thermal oxidation to convert a portion of the silicon of the semiconductor material to silicon dioxide and forming a first dielectric material over the first cavity, over the second cavity, over at least a portion of the semiconductor material, and over at least a portion of the first protrusion. Other embodiments are described and claimed.