Demonstration of Ultraviolet μLED Array With Novel Electrical Contact Etch Mask

Seitz, Matthew; Hartensveld, Matthew; Melanson, Bryan; Boisvere, Jacob; Zhang, Jing

doi:10.1109/jqe.2023.3310968

Cited by 5 publications

(4 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In many cases, vertical sidewalls are desired, but are difficult to obtain using dry etching alone. Fortunately, all of these issues can be addressed using a hydroxyl-based crystallographic wet etch [25][26][27][28]. Etching of GaN and its alloys using hydroxyl-based chemistries such as tetramethyl ammonium hydroxide (TMAH) and potassium hydroxide (KOH) has been extensively studied [25,28].…”

Section: Hydroxyl-based Etching Of Gan and Algan For Photonic Devicesmentioning

confidence: 99%

“…Fortunately, all of these issues can be addressed using a hydroxyl-based crystallographic wet etch [25][26][27][28]. Etching of GaN and its alloys using hydroxyl-based chemistries such as tetramethyl ammonium hydroxide (TMAH) and potassium hydroxide (KOH) has been extensively studied [25,28]. GaN alloys etching crystallographically in solutions containing hydroxide anions, as the difference wurtzite planes of GaN allows have differing levels of polarization, with strongly Ga-polar planes repelling OHanions much more strongly than N-polar planes.…”

Section: Hydroxyl-based Etching Of Gan and Algan For Photonic Devicesmentioning

confidence: 99%

“…In this study, dilute KOH solutions were used to determine the ideal solution temperature for wet etch passivation of GaN/AlGaN nanostructures. This work was built upon 2023 by Seitz et al, who further studied the effects of KOH concentration, temperature, and etch time on sidewall surface roughness and lateral etch rate, determining the ideal etch conditions for minimizing surface damage on smooth, vertical GaN/AlGaN sidewalls [28]. Seitz et al also showed that the presence of a Ni cap/etch mask on GaN micropillars during the KOH etching process can have a drastic effect on the resulting sidewall smoothness and lateral etched rate of these structures [28].…”

Section: Hydroxyl-based Etching Of Gan and Algan For Photonic Devicesmentioning

confidence: 99%

See 2 more Smart Citations

(Invited) III-Nitride Ultraviolet LEDs and Lasers for Applications in Biology and Medicine

Zhang,

Melanson,

Seitz

et al. 2024

ECS Trans.

View full text Add to dashboard Cite

Solid-state ultraviolet (UV) light emitters are being developed for emerging biomedical applications such as surface sterilization, air/water purification, and medical treatments as a replacement for mercury vapor lamps. While these UV emitters offer many advantages over mercury lamps, such as more compact form factors, tunable emission wavelengths, and greatly increased lifetimes, they also suffer from a number of issues which hinder their implementation in many potential applications. UV emitters are based on AlGaN heterostructures which usually have very poor external quantum efficiencies (EQEs) of less than 10%, with EQEs decreasing with emission wavelength. This makes it very challenging to realize high efficiency UV emitters whose high energy photons are capable of inactivating viruses, bacteria, and other pathogens. This work discusses recent developments made by the Zhang Research Group at the Rochester Institute of Technology in improving the efficiencies of UV LEDs and lasers.

show abstract

Section: Hydroxyl-based Etching Of Gan and Algan For Photonic Devicesmentioning

confidence: 99%

Section: Hydroxyl-based Etching Of Gan and Algan For Photonic Devicesmentioning

confidence: 99%

Section: Hydroxyl-based Etching Of Gan and Algan For Photonic Devicesmentioning

confidence: 99%

See 1 more Smart Citation

(Invited) III-Nitride Ultraviolet LEDs and Lasers for Applications in Biology and Medicine

Zhang,

Melanson,

Seitz

et al. 2024

ECS Trans.

View full text Add to dashboard Cite

show abstract

“…Demand for smaller electronic devices, more powerful computing, as well as brighter, higher resolution displays has driven the development of micropillar and nanowire (MP/NP) LEDs, [1], [2] lasers, [3] and transistors. [4] III-Nitrides, including gallium nitride (GaN), are especially well suited for these applications due to their wide bandgap, high electron mobility, and excellent thermal properties.…”

Section: Introductionmentioning

confidence: 99%

Surface passivation of GaN micropillar structures through KOH wet etch

Seitz,

Boisvere,

Melanson

et al. 2024

Gallium Nitride Materials and Devices XIX

Self Cite

View full text Add to dashboard Cite

Surface properties are important for structures such as micropillars and nanowires, which are critical for emerging devices including µLEDs, nano-lasers, and vertical power transistors due to increased surface to volume ratios. Fabrication of III-Nitride micropillars can be realized through a top-down approach, where structures are defined through lithography and reactive ion etching (RIE). While effective at forming these micropillar structures, RIE etching leaves behind roughened, non-vertical sidewalls. This surface damage increases non-radiative recombination, forms current leakage paths, and can severely degrade device performance. However, damage can be removed through a follow-up wet etch in potassium hydroxide (KOH) solution. KOH acts as a crystallographic etchant, preferentially exposing vertical <1-100> m-planes, producing smooth, vertical sidewalls.Here, we investigate KOH wet etch passivation for 2.5 µm diameter top-down fabricated GaN micropillars utilizing different temperatures and solution concentrations, and the effects of a Ni etch mask present during wet etching. We observed an average etch rate of 11.67 nm/min for micropillars etched in 60% AZ400k solution compared to 9.44 nm/min for micropillars etched in 20% AZ400k solution, both at a temperature of 80°C. At a constant 40% AZ400k concentration, an average etch rate of 14.39 nm/min for micropillars etched at 90°C are observed compared to 9.89 nm/min for micropillars etched at 70°C. Micropillars with a Ni etch mask present during KOH etching have an average etch rate of 9.46 nm/min compared to 12.83 nm/min for those without a Ni mask. The effects of KOH etching work to further optimize the performance of GaN-based micropillar and nanowire devices.

show abstract