Micro machined fuel gas combustion unit

The invention relates to a micro machined fuel gas combustion unit, comprising a substrate with at least one inlet for supplying fuel and oxygen-containing gas; a micro machined combustion tube connected to said inlet and arranged for chemically reacting the fuel to be measured with the oxygen containing gas in a combustion reaction therein; and at least one an outlet connected to said micro machined combustion tube for discharging waste gases produced in the combustion reaction. According to the invention said micro machined combustion tube is substantially thermally isolated to prevent heat loss to the surrounding, and the micro machined combustion tube has four walls defining a substantially rectangular cross section, wherein at least two opposing walls of the four walls of said combustion tube are provided with a reinforcing supporting structure

Microfabrication Technology for Isolated Silicon Sidewall Electrodes and Heaters

This paper presents a novel microfabricationtechnology for highly doped silicon sidewall electrodesparallel to – and isolated from – the microchannel. Thesidewall electrodes can be utilised for both electricaland thermal actuation of sensor systems. Thetechnology is scalable to a wide range of channelgeometries, simplifies the release etch, and allows forfurther integration with other Surface ChannelTechnology-based systems. Furthermore, thefabrication technology is demonstrated through thefabrication of a relative permittivity sensor. The sensormeasures relative permittivity values ranging from 1 to80, within 3% accuracy of full scale, including waterand water-containing mixtures

Method of fabricating a micro machined channel

The invention relates to a method of fabricating a micro machined channel, comprising the steps of providing a substrate of a first material and having a buried layer of a different material therein, and forming at least two trenches in said substrate by removing at least part of said substrate. Said trenches are provided at a distance from each other and at least partly extend substantially parallel to each other, as well as towards said buried layer. The method comprises the step of forming at least two filled trenches by providing a second material different from said first material and filling said at least two trenches with at least said second material; forming an elongated cavity in between said filled trenches by removing at least part of said substrate extending between said filled trenches; and forming an enclosed channel by providing a layer of material in said cavity and enclosing said cavity

Disposable DNA Amplification Chips with Integrated Low-Cost Heaters

Fast point-of-use detection of, for example, early-stage zoonoses, e.g., Q-fever, bovine tuberculosis, or the Covid-19 coronavirus, is beneficial for both humans and animal husbandry as it can save lives and livestock. The latter prevents farmers from going bankrupt after a zoonoses outbreak. This paper describes the development of a fabrication process and the proof-of-principle of a disposable DNA amplification chip with an integrated heater. Based on the analysis of the milling process, metal adhesion studies, and COMSOL MultiPhysics heat transfer simulations, the first batch of chips has been fabricated and successful multiple displacement amplification reactions are performed inside these chips. This research is the first step towards the development of an early-stage zoonoses detection device. Tests with real zoonoses and DNA specific amplification reactions still need to be done

Selective SiO2 etching in three dimensional structures using parylene-C as mask

This abstract describes an application of an easy and straightforward method for selective SiO2 etching in three dimensional structures, which is developed by our group. The application in this abstract is the protection of the buried-oxide (BOX) layer of a silicon-on-insulator (SOI) wafer against SiO2 hard mask stripping in BHF after deep reactive ion etching (DRIE) in the device layer, where the BOX layer serves as etch stop. It enables further processing like refilling of trenches and other structures with preservation of the BOX layer, which can serve as sacrificial layer or electrical isolation. The BOX layer protection is done with parylene-C. This is a poly(monochloro-p-xylylene) polymer, which is traditionally used to coat implantable devices, used as protective packaging material in (chemical) sensors, or as actual shapeable material in devices. The presented method adds mask material for selective SiO2 etching to the list

Thermal Flow Meter with Integrated Thermal Conductivity Sensor

This paper presents a novel gas-independent thermal flow sensor chip featuring three calorimetric flow sensors for measuring flow profile and direction within a tube, along with a single-wire flow independent thermal conductivity sensor capable of identifying the gas type through a simple DC voltage measurement. All wires have the same dimensions of 2000 (Formula presented.) m in length, 5 (Formula presented.) m in width, and 1.2 (Formula presented.) m in thickness. The design theory and COMSOL simulation are discussed and compared with the measurement results. The sensor’s efficacy is demonstrated with different gases, He, N2, Ar, and CO2, for thermal conductivity and thermal flow measurements. The sensor can accurately measure the thermal conductivity of various gases, including air, enabling correction of flow rate measurements based on the fluid type. The measured voltage from the thermal conductivity sensor for air corresponds to a calculated thermal conductivity of 0.02522 [W/m·K], with an error within 2.9%.</p