Podcast
Questions and Answers
What characteristic of the (111) plane in silicon contributes to its higher etch rate compared to the (100) and (110) planes?
What characteristic of the (111) plane in silicon contributes to its higher etch rate compared to the (100) and (110) planes?
- It has more dangling bonds. (correct)
- It possesses fewer dangling bonds.
- It has the most silicon atoms per unit area.
- It represents a higher density of crystal structure.
Which notation would be used to identify a family of equivalent planes including the (113) plane?
Which notation would be used to identify a family of equivalent planes including the (113) plane?
- [113]
- <113>
- (113)
- {113} (correct)
Why do orientation-dependent etchants exhibit different etch rates for the (100), (110), and (111) planes?
Why do orientation-dependent etchants exhibit different etch rates for the (100), (110), and (111) planes?
- The bonds of the silicon atoms in each plane are equally strong.
- The chemical composition of the etchant changes with each plane.
- Each plane exposes a varying number of silicon atoms to the etchant. (correct)
- Different planes have different temperatures.
What is the role of dangling bonds in the etching process of silicon planes?
What is the role of dangling bonds in the etching process of silicon planes?
What does a bar above an index indicate in the Miller representation?
What does a bar above an index indicate in the Miller representation?
What is a primary technique used to fabricate mechanical components in MEMS devices?
What is a primary technique used to fabricate mechanical components in MEMS devices?
Which of the following materials are commonly used in the fabrication of microstructures for MEMS?
Which of the following materials are commonly used in the fabrication of microstructures for MEMS?
Where are MEMS accelerometers commonly found?
Where are MEMS accelerometers commonly found?
What is a 'proof mass' in the context of MEMS devices?
What is a 'proof mass' in the context of MEMS devices?
What fabrication techniques are essential for making microstructures suitable for MEMS applications?
What fabrication techniques are essential for making microstructures suitable for MEMS applications?
What are the two main types of silicon etching techniques?
What are the two main types of silicon etching techniques?
Which type of etch stop is influenced by the concentration of materials?
Which type of etch stop is influenced by the concentration of materials?
Which micromachining technique involves using molds to shape materials?
Which micromachining technique involves using molds to shape materials?
What is one method used for wafer bonding?
What is one method used for wafer bonding?
Which material is NOT typically used in surface (sacrificial) micromachining?
Which material is NOT typically used in surface (sacrificial) micromachining?
What type of silicon micromachining utilizes both wet and dry processes?
What type of silicon micromachining utilizes both wet and dry processes?
Which etching technique is characterized by uniform etching rates in all directions?
Which etching technique is characterized by uniform etching rates in all directions?
What is an example of a micromachining technique that can be combined with molding?
What is an example of a micromachining technique that can be combined with molding?
What type of etching is characterized by the same rate of etching in all directions?
What type of etching is characterized by the same rate of etching in all directions?
Which etching method is specifically dependent on the crystal orientation of silicon?
Which etching method is specifically dependent on the crystal orientation of silicon?
What kind of etching uses the properties of pn junctions to halt the etching process?
What kind of etching uses the properties of pn junctions to halt the etching process?
Which etching method allows for a high degree of control over the etching profile of silicon structures?
Which etching method allows for a high degree of control over the etching profile of silicon structures?
Which statement is true regarding heavily-doped and lightly-doped etch stops?
Which statement is true regarding heavily-doped and lightly-doped etch stops?
What distinguishes dry etching from wet etching in micromachining processes?
What distinguishes dry etching from wet etching in micromachining processes?
Which etching method is best characterized by using plasmas to etch materials?
Which etching method is best characterized by using plasmas to etch materials?
What role does concentration play in wet etching processes?
What role does concentration play in wet etching processes?
What happens to the capacitance as the diaphragm deflects?
What happens to the capacitance as the diaphragm deflects?
What is the approximate thickness of the pressure sensing membrane mentioned?
What is the approximate thickness of the pressure sensing membrane mentioned?
Which of the following structures is NOT listed as a type of microstructure in MEMS?
Which of the following structures is NOT listed as a type of microstructure in MEMS?
Which of the following materials is indicated as part of the microstructures needed for MEMS?
Which of the following materials is indicated as part of the microstructures needed for MEMS?
What type of microphone is mentioned in the context of MEMS technology?
What type of microphone is mentioned in the context of MEMS technology?
How are the various sizes and shapes of microstructures relevant to MEMS?
How are the various sizes and shapes of microstructures relevant to MEMS?
What is the function of the variation in the gap in a capacitive microphone?
What is the function of the variation in the gap in a capacitive microphone?
Which technology is primarily associated with the creation of microstructures for MEMS?
Which technology is primarily associated with the creation of microstructures for MEMS?
Flashcards are hidden until you start studying
Study Notes
Overview of MEMS Technologies
- Silicon etching is a critical process in MEMS, encompassing isotropic and anisotropic methods, wet and dry techniques.
- Etch stops can be concentration-dependent, electrochemical, or dielectric, crucial for controlling etching processes.
- Wafer bonding techniques include anodic, fusion, eutectic, and polymer bonding, essential for integrating MEMS components.
Types of Silicon Etching
-
Wet Etching
- Sub-divided into isotropic and anisotropic etching based on the uniformity of etching.
- Concentration-dependent etching utilizes different doping levels to create etch stops.
- Electrochemical etch stops utilize pn junctions, while dielectric etch stops rely on layer characteristics.
-
Dry Etching
- Plasma etching and Deep Reactive Ion Etching (DRIE) are key methods used for precise etching.
Anisotropic Silicon Etching (ASE)
- ASE occurs with etchants that preferentially etch different silicon crystal orientations, leading to varied etching rates.
- The major crystallographic planes in silicon are represented as (100), (110), and (111), with different etch rates corresponding to the atomic density and dangling bonds of each plane.
- More dangling bonds in a plane result in a higher etch rate due to weaker atomic bonds.
Applications of MEMS
- MEMS accelerometers are integral in various devices, measuring movements in cars, phones, toys, and watches.
- Fabrication of mechanical components, such as proof mass, generally employs surface micromachining techniques.
- Capacitive pressure sensing uses membranes about 1µm thick and 1mm wide, recording changes via deflection that alters capacitance.
MEMS Microstructures
- A diverse range of microstructures (e.g., beams, membranes, bridges, tubes, pillars) are essential for various MEMS applications.
- The ability to manufacture complex microstructures from various materials is crucial for the functionality and deployment of MEMS devices.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
