Fabrication of GaN suspended microstructures

Strittmatter, Robert; Beach, Robin; McGill, T. C.

doi:10.1063/1.1364504

Cited by 32 publications

(16 citation statements)

References 12 publications

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“…Growth of III-N layers on Si (111) usually accumulates large residual strains, due to the 17% lattice mismatch. The relaxation of large biaxial strains after the micromachining step, either tensile or compressive, leads to a deformation of the free standing structure [3,4] which may render the device useless. These deformations are analysed in this work for several MEMS topologies.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and stress relief modelling of GaN based MEMS test structures grown by MBE on Si(111)

Sillero¹,

López-Romero²,

Bengoechea³

et al. 2008

Phys. Status Solidi (c)

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The fabrication of III-N MEMS test structures, such as cantilevers, beams and stress-pointers, and the modelling of their deformation due to residual stress relief, is presented. GaN and AlGaN/GaN structures were fabricated, either with one end and both ends clamped to the Si substrate (asymmetrical and symmetrical mechanical boundary conditions, respectively). The residual stress in the III-N layer was measured by photoluminescence and X-ray diffraction, and the stress relief induced deformation was analysed by a finite element method model. The deformations of the MEMS structures were used to calculate both the residual strains and the Youna's modulus of the material. One-end-clamped structures suffer from large deformations due to the uneven stress relaxation. During micromachining, the relaxation induces large upward buckling, as measured for fabricated devices and fitted by the FEM model. Two-end-clamped structures were also studied using different topologies and under-etching lengths of the clamped region. It is concluded that the deformation of such structures may be reduced with symmetrical mechanical boundary conditions and a small under-etched clamping region compared to the device dimensions.

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Section: Introductionmentioning

confidence: 99%

Fabrication and stress relief modelling of GaN based MEMS test structures grown by MBE on Si(111)

Sillero¹,

López-Romero²,

Bengoechea³

et al. 2008

Phys. Status Solidi (c)

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“…A GaN microfluidic channel produced by controlled and rapid undercutting of p -GaN epilayers with an extension of photo electrochemical etching is shown in Figures 32a-32c [44]. The microchannel consists of a 1-mm-thick p -GaN membrane that spans between 2 long anchoring strips on either side.…”

Section: Other Applicationsmentioning

confidence: 99%

“…The samples were immersed in 0.1 M KOH and exposed on the p-type layer side to UV radiation from a xenon arc lamp with power 100 mW/cm 2 [44]. Opaque metal masks have been patterned onto the samples prior to the PEC etching, so that the n -type epilayer does not etch in the areas below the masks, while it is etched in nonmasked regions.…”

Section: Fabrication Of Gan Membranes By Wet Etching Undercuttingmentioning

confidence: 99%

GaN nanostructuring for the fabrication of thin membranes and emerging applications

Tiginyanu¹,

Ursaki²

2014

Turk J Phys

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Abstract:We present a review of technological methods developed in recent years for the purpose of gallium nitride nanostructuring, with the main focus on fabrication of thin GaN membranes. In particular, we report on traditional methods of wet etching undercutting for membrane manufacturing, technologies applied for the fabrication of photonic crystal structures based on GaN nanomembranes, double side processing, and surface charge lithography. Prospects of membrane applications in photonic devices, sensors, and microoptoelectromechanical and nanoelectromechanical systems are discussed, taking into account the advantageous piezoelectric, optical, and mechanical properties of GaN and related III-V nitride materials.

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“…3 The development of sensors of this type is especially germane given the broad range of suspended micro-and nanomechanical structures that can now be fashioned in GaN. 4 Highly sensitive strain detectors, integrated on these platforms, would open the door for an entire family of diverse and flexible sensors using GaN.…”

Section: Introductionmentioning

confidence: 99%

Piezoelectrically enhanced capacitive strain sensors using GaN metal-insulator-semiconductor diodes

Strittmatter

Beach

Picus

et al. 2003

Journal of Applied Physics

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We report on the use of metal-insulator-semiconductor ͑MIS͒ diodes, formed on n-GaN with SiO 2 , for capacitive strain sensing. These diodes, when subjected to static strain, were found to exhibit a steady-state change in capacitance. As a result, they can be used to detect strain with frequencies all the way down to dc. We formulate a model to explain the action of piezoelectricity in the diode and obtain excellent agreement with measurements. The model is then used to develop design criteria which optimize the sensitivity of the diode to detect strain. The sensitivity of the devices tested here rivals that of the best silicon piezoresistive sensors, but could attain nearly tenfold improvement with only minor design changes. Finally, we consider the effects of interface states on sensor performance and demonstrate how static strain sensing in GaN MIS diodes is enabled by the high quality of the oxide interface.

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Fabrication of GaN suspended microstructures

Cited by 32 publications

References 12 publications

Fabrication and stress relief modelling of GaN based MEMS test structures grown by MBE on Si(111)

Fabrication and stress relief modelling of GaN based MEMS test structures grown by MBE on Si(111)

GaN nanostructuring for the fabrication of thin membranes and emerging applications

Piezoelectrically enhanced capacitive strain sensors using GaN metal-insulator-semiconductor diodes

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