A process to fabricate micro‐membrane of Si3N4 and SiO2 using front‐side lateral etching technology

Alvi, P. A.; Lourembam, B.D.; Deshwal, V.P.; Joshi, B. C.; Akhtar, Jamil

doi:10.1108/02602280610675456

Cited by 12 publications

(5 citation statements)

References 7 publications

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“…The range can be adjusted by further thinning down the separation gap between the two cavities. If compared with a single cavity absolute pressure sensor of the size of 0.1 mm (Alvi et al , 2006), the two cavity configuration in the same area of 0.1 mm provides enhanced pressure range with reduced sensitivity. The two cavity concept has potentials for flow rate sensing of gases and liquids.…”

Section: Resultsmentioning

confidence: 99%

“…The first micromechanical sensor was the piezoresistive pressure sensor, which was developed at Bell Labs in 1960. Very thin, supported membranes of silicon, silicon dioxide, silicon nitride and their combinations have been developed using bulk micromachining from back side of the silicon wafer (Kressmann et al , 2002), front‐side etching technology (Peng et al , 2005) based on etching via hole from the front side of the wafer and front‐side lateral etching technology (Alvi et al , 2006) on silicon substrate. These membranes would bend in response to applied pressure.…”

Section: Introductionmentioning

confidence: 99%

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Fabrication of a membrane type double cavity vacuum‐sealed micro sensor for absolute pressure based on front‐side lateral etching technology

Rathore

Akhtar

2011

Sensor Review

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PurposeThe purpose of this paper is to describe the fabrication of a miniaturized membrane type double cavity vacuum‐sealed micro sensor for absolute pressure using front‐side lateral etching technology.Design/methodology/approachPotassium hydroxide‐based anisotropic etching of single crystal silicon is used to realize the cavities under the membrane type diaphragms through channels on the sides. The diaphragms consist of composite layers of plasma‐enhanced chemical vapour deposition (PECVD) of silicon nitride and silicon dioxide. PECVD of silicon dioxide is done for sealing the channels and the cavity in vacuum. Boron thermal diffusion in low‐pressure chemical vapour deposition of polysilicon layer over the membrane is done for realizing resistors. The fabricated device uses Wheatstone half bridge circuit to read the variation of resistance with respect to an applied pressure.FindingsA double cavity vacuum‐sealed absolute pressure micro sensor has been fabricated successfully using front‐side lateral etching technology and has been measured for pressure range of 0‐0.45 MPa. The measured pressure sensitivity of two pressure sensors is 9.28 and 10.44 mV/MPa.Originality/valueThe paper shows that front‐side lateral etching technology is feasible in the fabrication of small vacuum‐sealed cavities and absolute pressure sensors.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fabrication of a membrane type double cavity vacuum‐sealed micro sensor for absolute pressure based on front‐side lateral etching technology

Rathore

Akhtar

2011

Sensor Review

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“…As a result, anisotropic etching of silicon has been an important process in the technologies for attaining three-dimensional structures. [8]. The chemical etching of Si is affected by crystallographic planes, temperature, and etchant concentration.…”

Section: Introductionmentioning

confidence: 99%

Morphological and Optical Study of Black P- Silicon Textured in KOH Bath

Ibrahim

Noori

Hwail

et al. 2023

DFMA

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This paper reports the temperature and the concentration dependence of anisotropic etching for (100) p-Silicon in an aqueous KOH solution etching rate of wet etching has been experimentally determined with varying concentrations and the temperature of the KOH solution. The texturing process was managed at different etching durations ( 20 min, 40 min, and 60 min). XRD test showed that the lowest value of grain size was 5.0 nm (obtained with the highest porosity percentage of 50% with 4.5% KOH concentration for 60 min). FESEM test showed that the pore diameter increased with increasing etching time. The lowest reflectance value was (2.8 % at 550 nm wavelengths for samples treated with 4.5% KOH concentration for 60 min etching time. The refractive index value was 1.8 for the same black Si sample, also Hall test is introduced.

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“…In the applications of temperature sensing devices, it is supposed to show high TCR; while on the other hand, a resistor for reliable circuits ought to have a totally low TCR [35]. Some early results of the research work on low pressure measurement have been presented in [36][37][38][39][40][41].…”

Section: Introductionmentioning

confidence: 99%

Influence of the pressure range on temperature coefficient of resistivity (TCR) for polysilicon piezoresistive MEMS pressure sensor

2020

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Sensitivity with respect to physical change of any type of sensor depends upon structure of the sensor and sensing material. If sensor is sensitive with more than single physical change (pressure or temperature etc) than sensitivity will get affected because of conflict in impact due to multiple physical parameters. Depending upon the designer’s intuition and experience, a variety of shapes of sensor had been proposed which can bear both the pressure and temperature. To understand the influence of temperature and pressure on the linearity and sensitivity, pressure sensors has been designed having 50 μm thick square diaphragm is being simulated and analyzed. The effect of pressure on Temperature Coefficient of Resistivity (TCR) of poly-silicon pressure sensor has been investigated in this paper. The stresses tempted in the piezoresistors and dislocation created in diaphragm have been studied using finite element method (FEM). The physical characteristics of sensor have been determined within the temperature range from 10 °C to 100 °C under the pressure range of 0 to 100 psi. It has been observed that TCR reduces with increasing pressure up to 30 psi, and beyond this pressure, the TCR begins to increase and thus the TCR shows the duality in nature. At 100 psi pressure, the calculated TCR for the diaphragm is found of the order of ∼7.7 × 10−3 (/°C). Thus, in conclusion, the pressure range ∼40–100 psi is recommended as the optimal range to achieve the better sensitivity. The temperature sensitivity of designed sensor has been found to be ∼0.10455 mV °C−1 while the pressure sensitivity of the proposed sensors which has been found to be 1.20051 mV psi−1. Hence, designed sensor can be used as both pressure and temperature sensing device incorporated into a single sensor.

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A process to fabricate micro‐membrane of Si₃N₄ and SiO₂ using front‐side lateral etching technology

Cited by 12 publications

References 7 publications

Fabrication of a membrane type double cavity vacuum‐sealed micro sensor for absolute pressure based on front‐side lateral etching technology

Fabrication of a membrane type double cavity vacuum‐sealed micro sensor for absolute pressure based on front‐side lateral etching technology

Morphological and Optical Study of Black P- Silicon Textured in KOH Bath

Influence of the pressure range on temperature coefficient of resistivity (TCR) for polysilicon piezoresistive MEMS pressure sensor

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