Bulk micromachining of SiC substrate for MEMS sensor applications

Vanko, G.; Hudek, P.; Zehetner, Johann; Dzuba, J.; Choleva, Pavlina; Kutiš, Vladimı́r; Vallo, Martin; Rýger, Ivan; Lalinský, T.

doi:10.1016/j.mee.2013.01.046

Cited by 33 publications

(12 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…substrate, we produced an array of 250 µm deep and 500 µm diameter blind holes without damaging the adjacent layer of heterostructures. It was shown that 4H-SiC 80 µm thick diaphragms can be fabricated five times faster with laser ablation in comparison to (RIE) (Vanko et al 2013). We now also investigate ferroelectric thin films as they can be deposited and micro-patterned by a direct UVlithography method after the ablation process for a specific membrane design (Benkler et al 2014).…”

Section: Introductionmentioning

confidence: 97%

Manufacturing of membranes by laser ablation in SiC, sapphire, glass and ceramic for GaN/ferroelectric thin film MEMS and pressure sensors

et al. 2016

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 97%

Manufacturing of membranes by laser ablation in SiC, sapphire, glass and ceramic for GaN/ferroelectric thin film MEMS and pressure sensors

et al. 2016

View full text Add to dashboard Cite

“…We verified the feasibility to fabricate micro mechanic structures in bulk SiC substrates with epitaxial AlN/AlGaN/GaN heterostructures by femtosecond laser ablation at 520nm wavelength in combination with RIE for pressure sensor applications. On a 4H-SiC substrate we produced an array of 250µm deep and 500µm diameter blind holes without damaging the AlGaN/GaN heterostructures 5 . We now also investigate ferroelectric thin films as they can be deposited and micro-patterned by a direct UV-lithography method after the ablation process for a specific membrane design 6 .…”

Section: Introductionmentioning

confidence: 99%

Laser ablation for membrane processing of AlGaN/GaN- and micro structured ferroelectric thin film MEMS and SiC pressure sensors for extreme conditions

Zehetner¹,

Vanko²,

Dzuba³

et al. 2015

SPIE Proceedings

View full text Add to dashboard Cite

AlGaN/GaN based high electron mobility transistors (HEMTs), Schottky diodes and/or resistors have been presented as sensing devices for mechanical or chemical sensors operating in extreme conditions. In addition we investigate ferroelectric thin films for integration into micro-electro-mechanical-systems (MEMS). Creation of appropriate diaphragms and/or cantilevers out of SiC is necessary for further improvement of sensing properties of such MEMS sensors. For example sensitivity of the AlGaN/GaN based MEMS pressure sensor can be modified by membrane thickness. We demonstrated that a 4H-SiC 80µm thick diaphragms can be fabricated much faster with laser ablation than by electrochemical, photochemical or reactive ion etching (RIE). We were able to verify the feasibility of this process by fabrication of micromechanical membrane structures also in bulk 3C-SiC, borosilicate glass, sapphire and Al 2 O 3 ceramic substrates by femtosecond laser (520nm) ablation. On a 350µm thick 4H-SiC substrate we produced an array of 275µm deep and 1000µm to 3000µm of diameter blind holes without damaging the 2µm AlN layer at the back side. In addition we investigated ferroelectric thin films as they can be deposited and micro-patterned by a direct UV-lithography method after the ablation process for a specific membrane design. The risk to harm or damage the function of thin films was eliminated by that means. Some defects in the ablated membranes are also affected by the polarisation of the laser light. Ripple structures oriented perpendicular to the laser polarisation promote creation of pin holes which would perforate a thin membrane. We developed an ablation technique strongly inhibiting formation of ripples and pin poles.

show abstract

“…Their salient properties are a high electrical resistance, a high thermal conductivity and a great chemical resistance. With respect to their application in micro tooling, hot embossing dies for microfluidics, electronics and sensing both the ceramic micro structuring of the surface as well as the volume (3D structures) is of upmost importance [8]. Decreasing feature size and increasing requirements on quality and cost efficiency, expedite a further development of precise and efficient ablation processes with high removal rates and attainable surface roughness allowing the fabrication of complex 3D structures for, e.g., tooling inserts, to be fabricated [5].…”

Section: Introductionmentioning

confidence: 99%

Micromachining of AlN and Al2O3 Using Fiber Laser

2014

View full text Add to dashboard Cite

Abstract:We report on high precision high speed micromachining of Al2O3 and AlN using pulsed near infrared fiber laser. Ablation thresholds are determined to be 30 J/cm 2 for alumina and 18 J/cm 2 for aluminum nitride. The factors influencing the efficiency and quality of 3D micromachining, namely the surface roughness, the material removal rate and the ablation depth accuracy are determined as a function of laser repetition rate and pulse overlap. Using a fluence of 64 J/cm², we achieve a material removal rate of up to 94 mm³/h in Al2O3 and 135 mm³/h in AlN for high pulse overlaps (89% and 84%). A minimum roughness of 1.5 μm for alumina and 1.65 μm for aluminum nitride can be accomplished for medium pulse overlaps (42% to 56%). In addition, ablation depth deviation of the micromachining process of smaller than 8% for alumina and 2% for aluminum nitride are achieved. Based on these results, by structuring exemplarily 3D structures we demonstrate the potential of high quality and efficient 3D micromachining using pulsed fiber laser.

show abstract

Bulk micromachining of SiC substrate for MEMS sensor applications

Cited by 33 publications

References 22 publications

Manufacturing of membranes by laser ablation in SiC, sapphire, glass and ceramic for GaN/ferroelectric thin film MEMS and pressure sensors

Manufacturing of membranes by laser ablation in SiC, sapphire, glass and ceramic for GaN/ferroelectric thin film MEMS and pressure sensors

Laser ablation for membrane processing of AlGaN/GaN- and micro structured ferroelectric thin film MEMS and SiC pressure sensors for extreme conditions

Micromachining of AlN and Al2O3 Using Fiber Laser

Contact Info

Product

Resources

About