Photoluminescence mapping of the strain induced in InP and GaAs substrates by SiN  stripes etched from thin films grown under controlled mechanical stress

2020

Appl. Opt.

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Experimentally it is known that the degree of polarization (DOP) of luminescence is a sensitive function of strain in III-V materials. It has been assumed that DOP = −K e (e 1 − e 2) and that the rotated degree of polarization (ROP) = 2 K e e 6 , where K e is a positive calibration constant, e 1 and e 2 are the normal components of strain along perpendicular '1' and '2' directions, and e 6 = e 12 is the tensor shear strain. K e has been measured experimentally for GaAs and InP. In this paper, the results of a simple analytic determination of expressions for DOP as a function of strain are presented. Given the wide ranges reported for the strain deformation potentials b and d, it is not possible to give definitive and meaningful numerical values for expressions for DOP and K e. However, the sensitivity of DOP to strain suggests that it might be possible to design simple experiments to provide accurate values for the deformation potentials. The b and d deformation potentials might not be independent. For the results presented here and in the limit of isotropic material, an isotropic result for the DOP is found if d = √ 3 b.

“…This α = 45 deg example is the case for measurements of a [110] oriented oxide stripe on a (001) growth surface withĥ across the stripe andv along the length of the stripe [28,29,55].…”

Section: Rop <001>mentioning

confidence: 99%

Degree of polarization of luminescence from GaAs and InP as a function of strain: a theoretical investigation

Cassidy

2020

Appl. Opt.

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“…Recent results illustrating these approaches, as well as detailed formulations, can be found in [19][20][21] . In this paper, we discuss results obtained from the spectral shift of the intrinsic CL emission (SS-CL), the degree of polarization of the PL (DOP-PL), and the degree of polarization of the CL (DOP-CL) intrinsic emission.…”

Section: Measurement Techniquesmentioning

confidence: 99%

“…The samples were scanned on both the top (100) surface across the etched ridges and a cleaved (110) surface in the area of the etched ridges. spectral shift to a volume change, the following formula was used 21 :…”

Section: Measurement Techniquesmentioning

confidence: 99%

“…Indeed, any non-zero ϵ yy should be almost constant along the ridge since the length can be considered infinite. This would induce an overall curvature of the sample in the y direction 21 . Such curvature was not observed indicates a compressive transverse strain ϵ xx within the ridge, with maxima at the edges, and a tensile transverse strain outside.…”

Section: Degree Of Polarization Of the Photoluminescence (Dop-pl)mentioning

confidence: 99%

“…The SiN x mask layer can induce mechanical stress after the PECVD deposition process 21 . This mechanical stress can be controlled by changing the PECVD conditions.…”

Section: Degree Of Polarization Of the Photoluminescence (Dop-pl)mentioning

confidence: 99%

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Mechanical stress in InP and GaAs ridges formed by reactive ion etching

Journal of Applied Physics

Fouchier

Pargon

et al. 2020

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The mechanical deformation induced by reactive ion etching (RIE) of rectangular ridge waveguides in GaAs and InP has been investigated by photoluminescence and cathodoluminescence techniques. Several trends were identified and are discussed.First, it is concluded that the RIE process itself is the source of the mechanical deformation. A compressive volume change occurs mainly within the ridge (with a maximum close to the vertical etched sidewalls), extending outside the ridges, up to several µm below the bottom etched surface. An anisotropic deformation also appears, again mainly close to the etched sidewalls and below the bottom etched surface. A narrow area under tensile stress was also identified, localized outside the ridges and in a shallow region below the bottom etched surface. Cumulative, overlapping effects are seen, inside the ridges where the compressive stress fields originating at the vertical etched sidewalls contribute to an overall compression inside the ridge which increases as the ridge width decreases. In addition, a tensile stress is also observed outside the ridge, strongly enhanced by the presence of neighbouring ridges. These conclusions are significant for the design of photonic structures. Because of the photoelastic effect, which is important in GaAs and InP, the properties of devices such as waveguides might be affected by the mechanical stress described herein.

Strain engineering in III-V photonic components through structuration of SiNx films

Ahammou

Abdelal

Journal of Vacuum Science &Amp; Technology B

et al. 2021

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We describe work to quantify the effects of structured dielectric thin films, such as SiNx, at the surface of III-V semiconductors, in terms of strain engineering with applications to photonic components such as waveguides and lasers. We show that the strain in the semiconductor can be engineered by controlling the stress in the dielectric thin film by tuning its deposition process. In the first part of this study, we describe how we can control the amount of this built-in mechanical stress, in the case of SiNx, over a large range, from highly tensile (300 MPa) to highly compressive (-800 MPa), using two different kinds of plasma-enhanced chemical vapor deposition reactors: a standard capacitively-coupled reactor with radio-frequency excitation and an electron cyclotron resonance reactor with micro-wave excitation. We focused on characterizing and understanding these thin films' optical and chemical bonding properties through spectroscopic ellipsometry and Fourier transform infrared spectroscopy. We have also studied their mechanical properties experimentally using the wafer curvature measurement technique, microstructure fabrication, and nano-indentation measurements. In the second part, we show accurate