Atomic layer epitaxy of AlGaN

Nagamatsu, Kentaro; Iida, Daisuke; Takeda, Kenta; Nagata, Kouji; Asai, Toshiaki; Iwaya, Motoaki; Kamiyama, Satoshi; Amano, Hiroshi; Akasaki, Isamu

doi:10.1002/pssc.200983862

Cited by 5 publications

(3 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, adduct polymerization depletes the source materials because particle contamination prevents crystal growth. This problem may be resolved by an alternative supply method from aluminum and nitrogen sources, as reported by Adivarahan et al and in other works 15 – 18 . This method not only suppresses the parasitic reaction but also enhances Al migration over the substrate surface; however, it is difficult to increase the growth rate in principle.…”

Section: Introductionmentioning

confidence: 86%

Reduction of parasitic reaction in high-temperature AlN growth by jet stream gas flow metal–organic vapor phase epitaxy

Nagamatsu

Tsuda

Miyagawa

et al. 2022

Sci Rep

Self Cite

View full text Add to dashboard Cite

AlGaN-based deep ultraviolet light-emitting diodes (LEDs) have a wide range of applications such as medical diagnostics, gas sensing, and water sterilization. Metal–organic vapor phase epitaxy (MOVPE) method is used for the growth of all-in-one structures, including doped layer and thin multilayers, using metal–organic and gas source raw materials for semiconductor devices. For AlN growth with high crystalline quality, high temperature is necessary to promote the surface migration of Al atoms and Al-free radicals. However, increase in temperature generates parasitic gas-phase prereactions such as adduct formation. In this work, AlN growth at 1500 °C by a stable vapor phase reaction has been achieved by jet stream gas flow metal–organic vapor phase epitaxy. The AlN growth rate increases with gas flow velocity and saturates at ~ 10 m/s at room temperature. Moreover, it is constant at an ammonia flow rate at a V/III ratio from 50 to 220. These results demonstrate the reduction in adduct formation, which is a typical issue with the vapor phase reaction between triethylaluminum and ammonia. The developed method provides the in-plane uniformity of AlN thickness within 5%, a low concentration of unintentionally doped impurities, smooth surface, and decrease in dislocation density because of the suppression of parasitic reactions.

show abstract

Section: Introductionmentioning

confidence: 86%

Reduction of parasitic reaction in high-temperature AlN growth by jet stream gas flow metal–organic vapor phase epitaxy

Nagamatsu

Tsuda

Miyagawa

et al. 2022

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…As the Al composition, x, in Al x Ga 1-x N increases, the Mg impurity activation energy increases (4), while the Si impurity undergoes a DX transition beyond x~ 0.84 (5,6), leading to rapidly decreasing free carrier concentrations in high Al content layers. Furthermore, the free carrier concentrations for both dopants are limited at high doping levels by the onset of compensation mechanisms involving vacancies and their complexes (7)(8)(9)(10)(11). In contrast to this approach, doping in compositionally graded AlGaN epilayers by taking advantage of the distributed polarization charge has been demonstrated for both n-type (12) and p-type (13) doping.…”

Section: Introductionmentioning

confidence: 99%

(Invited) Polarization-Induced Doping in Graded AlGaN Epilayers Grown on AlN Single Crystal Substrates

Dalmau

Moody

2018

ECS Trans.

View full text Add to dashboard Cite

Compositionally graded Al x Ga1-x N epilayers were coherently grown on AlN single crystal substrates by MOCVD, and polarization-induced doping was determined by contactless sheet resistance and capacitance-voltage measurements on unintentionally doped, n-type graded layers; and by temperature-dependent Hall effect measurements on a Mg doped, p-type graded layer. The room-temperature resistivity, hole concentration, and hole mobility of the p-type layer graded from x= 1.0 to x= 0.36 were 1.2 Ωcm, 4.5x1018 cm-3, and 1.2 cm2/Vs, respectively, which represents a significant improvement over traditional, thermally-activated Mg doping in AlGaN alloys.

show abstract

“…n recent years, considerable advancements in fabrication technology have enabled the development of high-performance AlGaN-based ultraviolet (UV) light-emitting devices with pn junctions. These achievements are primarily driven by improvements in the quality of AlN templates, such as high-quality AlN on sapphire substrates [1][2][3] and bulk AlN substrates, 4,5) along with enhanced control over n-and p-type conductivity through Si and Mg doping [6][7][8] and polarization doping. [9][10][11] Consequently, AlGaN-based UV-light-emitting diodes (LEDs) have been fabricated, exhibiting an impressive external quantum efficiency of ∼10% over a wide spectral range of 250-365 nm.…”

mentioning

confidence: 99%

Fabrication of vertical AlGaN-based ultraviolet-B laser diodes using a laser lift-off method

Nishibayashi,

Kondo,

Matsubara

et al. 2023

Appl. Phys. Express

View full text Add to dashboard Cite

Vertical AlGaN-based UV-B laser diodes were fabricated by a laser lift-off method to exfoliate sapphire substrates. These devices were processed on 1-cm2 square wafers with a polycrystalline sintered AlN substrate as a structural support for the exfoliated device. Following electrode formation and other necessary processing steps, mirrors were formed through cleavage. Subsequently, the performance of the device was evaluated by injecting a pulsed current at room temperature. Results revealed distinct characteristics, including a sharply emission at 298.1 nm, a well-defined threshold current, strong transverse-electric polarization characteristic, and a laser-specific spot-like far-field pattern, confirming the oscillation of the vertical laser diode.

show abstract

Atomic layer epitaxy of AlGaN

Abstract: The special pair of the bacterial photosystem has been modeled with a porphyrin dimer (the partial structure is shown). As with the natural system, only one pyrrole ring from each monomer subunit participates in π overlap.

Cited by 5 publications

References 11 publications

Reduction of parasitic reaction in high-temperature AlN growth by jet stream gas flow metal–organic vapor phase epitaxy

Reduction of parasitic reaction in high-temperature AlN growth by jet stream gas flow metal–organic vapor phase epitaxy

(Invited) Polarization-Induced Doping in Graded AlGaN Epilayers Grown on AlN Single Crystal Substrates

Fabrication of vertical AlGaN-based ultraviolet-B laser diodes using a laser lift-off method

Contact Info

Product

Resources

About