Fabrication of Smooth GaN-Based Laser Facets

Stocker, D. A.; Schubert, E. Fred; Boutros, K. S.; Redwing, Joan M.

doi:10.1557/s1092578300003446

Cited by 8 publications

(6 citation statements)

References 17 publications

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“…According to a previous TEM analysis performed on similar samples, this value is quite close to the effective density of dislocations. 21 Additionally, our plan-view TEM observations carried out on HVPE-grown samples revealed dislocation densities in the range 0.5-2ϫ10 9 cm Ϫ2 .…”

Section: Resultsmentioning

confidence: 73%

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Highly selective photoelectrochemical etching of nitride materials for defect investigation and device fabrication

Visconti¹,

Reshchikov²,

Jones³

et al. 2001

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Photoenhanced electrochemical ͑PEC͒ etching in an unstirred KOH solution under He-Cd laser illumination was used for delineating extended defects in GaN films. When a low-excitation intensity was employed, the process yielded threading vertical features at dislocation sites. Application of an external voltage or a higher-illumination intensity led to high-etch rates with smooth surfaces. Some highly resistive samples, for which no etching was obtained under normal etching conditions, could be etched with the application of a single-polarity external voltage. Finally, in a GaN sample with an AlN/GaN superstructure inside, high selectivity between AlN and GaN was achieved; in this case, the PEC process stopped at the thin AlN stop layer.

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Section: Resultsmentioning

confidence: 73%

“…Photoenhanced electrochemical ͑PEC͒ wet etching has been demonstrated to produce high-etch rates and anisotropic etch profiles in GaN films at room temperature. [16][17][18][19][20][21][22] Compared to dry-etching processes, PEC etching has the advantage of low surface damage, low equipment cost, and simplicity.…”

Section: Introductionmentioning

confidence: 99%

Highly selective photoelectrochemical etching of nitride materials for defect investigation and device fabrication

Visconti¹,

Reshchikov²,

Jones³

et al. 2001

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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“…The high-magnification SEM image (the inset in figure 1(a)) shows a typical hexagonal pit of a size of about 500 nm formed after 5 min etching at 20 torr. From inclined angles of etched GaN hexagonal facets, the planes are likely to be (1 0 1x), where x = 1, 2 or 3 [12]. However, the origin of the hexagonal etch pit is still unclear.…”

Section: Resultsmentioning

confidence: 99%

Etching of GaN by microwave plasma of hydrogen

Tiwari¹,

Chang²

2010

Semicond. Sci. Technol.

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An etching process for GaN on a sapphire substrate using a microwave plasma of hydrogen has been studied. Scanning electron microscopy observations of the surface morphology show that the etching of GaN with H 2 plasma can lead to the formation of etch pits in hexagonal shape. The average size of hexagonal pits is greater than 200 nm. The effects of processing pressure and etching time are demonstrated.

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“…Thus, there have been several attempts to utilize assisted wet-etching techniques. Photo-enhanced electro-chemical (PEC) etching has been demonstrated to produce high etch rates and anisotropic etch profiles in GaN films at room temperature [7,8,9,10,11]. Compared to dry etching processes, PEC etching has the advantage of low surface damage, low equipment cost and simplicity.…”

Section: Introductionmentioning

confidence: 99%

Highly selective photoenhanced wet etching of GaN for defect investigation and device fabrication

et al. 2000

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Photoenhanced electro-chemical (PEC) wet etching has been shown to be suitable for dislocation-density estimation in n-GaN films as well as for GaN-based device fabrication. We report on PEC etching of n-GaN samples grown by MBE and HVPE methods in unstirred aqueous KOH solution under He-Cd laser illumination. Characterization of the etched samples was carried out using atomic force microscopy (AFM) in both cross-sectional and plan-view configurations and scanning electron microscopy (SEM). At moderate illumination densities, the SEM and AFM analyses reveal sub-100 nm scale threading vertical wires on the etched surfaces. The calculated density (∼1×10 9cm−2) is in agreement with dislocation density found by transmission electron microscopy. Using cross-sectional AFM, we find that these vertical wires are ∼1[.proportional]m high and are perpendicular to the sapphire surface. Applying a higher illumination density or an external voltage, we obtain a higher etch rate with a smooth free-feature etched surface. Some highly resistive samples that cannot be etched under normal conditions because the band bending is too small to confine the holes to the surface for them to participate in the PEC process, can be etched with the application of a voltage to the sample. In this case, the etch rate depends on both the polarity and the magnitude of the voltage applied. In an MBE-grown sample with an AlN/GaN superstructure inside, we report on high selectivity between AlN and GaN (AlN is an etch stop); the selectivity is due to the etching mechanism of the PEC process.

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Fabrication of Smooth GaN-Based Laser Facets

Cited by 8 publications

References 17 publications

Highly selective photoelectrochemical etching of nitride materials for defect investigation and device fabrication

Highly selective photoelectrochemical etching of nitride materials for defect investigation and device fabrication

Etching of GaN by microwave plasma of hydrogen

Highly selective photoenhanced wet etching of GaN for defect investigation and device fabrication

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