Chemical etching control during the self-limitation process by boron diffusion in silicon: Analytical results

Găiseanu, F.; Tsoukalas, D.; Estéve, J.; Postolache, C.; Goustouridis, D.; Tsoi, E.

doi:10.1109/smicnd.1997.651590

Cited by 9 publications

(8 citation statements)

References 6 publications

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“…Even so, no correlation between diffusion profile and etching rate was reported up to date within the frame of the bulk micromachining technology, although this is a key requirement for an accurate control of the MEMS sensitive elements, particularly of the silicon membranes of the capacitive sensors for biomedical applications, so this problem is approached here, referring specifically to the preparation of the capacitive silicon sensors to measure the blood pressure. These miniature sensors (with area of the order of a few millimeters and the membrane diameter of the order of 100 micrometers) [5][6][7] can be implanted in the human body and can be monitored telemetrically without wires breaking the skin [8]. These sensors can provide a dynamic range of 0-50 mmHg over atmospheric pressure and their sensitivity response can be calculated as a function of their geometrical and material characteristics [9,10].…”

Section: Introductionmentioning

confidence: 99%

"Technology for the Accurate Preparation of Silicon Capacitive Pressure Sensors with Biomedical Application"

Gaiseanu¹

2022

BJSTR

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The boron diffusion in silicon from oxidation-assisted (BBr 3 and B 2 O 3 ) diffusion sources is an effective technique to obtain highly boron-doped silicon layers, which become stop layers for the subsequent chemical etching process to achieve silicon membranes for capacitive pressure sensors for biomedical applications. The control of the physical properties of such membranes depends therefore first of all on the diffusion process, which establishes both the thickness, its uniformity and the mechanical behavior of the membranes, with ultimate effect on the device characteristics, i.e. the linearity and capacity range variation. In this paper it is presented a method for an accurate control of the membrane thickness of silicon capacitive sensors for biomedical applications, by the calculation of the boron diffusion profile in silicon at high concentration, which shows a dependence of the diffusion coefficient on the square root of the boron concentration. An analytical solution of the diffusion equation is presented in the high concentration range (higher than 0.9-1.8×10 19 cm -3 for diffusion temperatures in the range 1050°C-1200°C), allowing an accurate calculation of the etching rate and of the etching time, necessary to control the thickness and the stress-inducing layers of the capacitive pressure sensors membranes, serving thus for an accurate achievement of the designed sensors and their required characteristics.

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Section: Introductionmentioning

confidence: 99%

"Technology for the Accurate Preparation of Silicon Capacitive Pressure Sensors with Biomedical Application"

Gaiseanu¹

2022

BJSTR

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“…However, as it was previously shown, the distribution of the boron concentration in silicon depends on the diffusion source and on the diffusion depth, so a distinct analysis of the etching process should be applied in each distinct case. Such an analysis was reported for boron doped layers after diffusion from solid boron nitride BN source [4] and for boron implantation 1 PhD, Solid State Physics (University of Bucharest), Principal Senior Researcher (Professor), Science and Technology of Information Bucharest (Romania) and Barcelona (Spain) -(e-mail: fgtext@yahoo.es).…”

Section: Introductionmentioning

confidence: 88%

ANALYTICAL MODELING AND SIMULATION OF THE CHEMICAL ETCHING PROCEss OF THE BORON-DOPED SILICON LAYERS FROM BBr3 SOURCE in the micromachining technology

Găiseanu¹

2021

AnnalsARSciInfo

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The boron-doped silicon layers commonly used to fabricate various micro-mechanical elements, particularly silicon membranes, are efficient stop-etching barriers, so their control is crucial in the bulk micromachining technology. As the properties of the boron doped layers depends on the type of the doping source and on the diffusion depth in the silicon bulk, a particular analysis should be applied in each specific case. In this paper there are reported the results of an analytical modeling of the boron diffusion profile in silicon, which are applied to simulate the boron diffusion profile at high diffusion temperatures (1050°C, 1100°C, 1150°C and 1200°C), emphasizing a dependence of the diffusion coefficient as a square root of the boron diffusion concentration. It is shown that the comparison of the theoretical results and some experimental diffusion data after diffusion at 1050°C shows a very good agreement, well supporting the analytical modeling. On this basis, the chemical etching rate and the etching time are simulated as a function of the boron diffusion depth in silicon for various etching solutions and etching conditions, providing suitable guiding curves for practical applications in the bulk micromachining technology

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“…This boron layer is located at the center of the sensor to enable conversion of IR radiation into heat necessary for operation of the thermopile. We positioned the absorber area under the membrane because the high concentration of boron carriers becomes effective stop-layers during the chemical etching [21] of silicon when the membrane is released. Figure 6 shows the SIMS doping profiles on which we measured a concentration of 1 -1.5 × 10 20 cm −3 carriers over a depth of about 3 -5 µm.…”

Section: Manufacturing Of Micromachined Dual Line Thermopile Sensor Amentioning

confidence: 99%

Advanced Thermopile IR Dual Line Sensor for Smart Home

Escriba¹,

Roux²,

Soto-Romero³

et al. 2018

JST

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This article presents all steps between the advanced design and the production of CMOS compatible thermoelectric effect infrared sensors dedicated to smart home applications. It will start by making a comparison between thermopile, bolometer and pyroelectric technologies. Although sensitivity performances available with bolometers appear to be better at first sight, it is found that thermopiles have non-negligible advantages that make them more suitable for this application field. Then the different steps necessary for the design will be described, starting from the thermoelectric model of the sensor (temperature gradient, electrical sensitivity, etc.) and considering all steps up to technological manufacturing in a clean room. The results obtained on the structures produced on a specific computer-controlled measurement bench (temperature regulation with an onboard preamplification card) will be presented. Finally, the results prove that the square structures have better performances (S = 82 V/W and NETD = 208 mK).

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Chemical etching control during the self-limitation process by boron diffusion in silicon: Analytical results

Cited by 9 publications

References 6 publications

"Technology for the Accurate Preparation of Silicon Capacitive Pressure Sensors with Biomedical Application"

"Technology for the Accurate Preparation of Silicon Capacitive Pressure Sensors with Biomedical Application"

ANALYTICAL MODELING AND SIMULATION OF THE CHEMICAL ETCHING PROCEss OF THE BORON-DOPED SILICON LAYERS FROM BBr3 SOURCE in the micromachining technology

Advanced Thermopile IR Dual Line Sensor for Smart Home

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