Characterization and optimization of sputtered AlN buffer layer on r-plane sapphire substrate to improve the crystalline quality of nonpolar a-plane GaN

Jinno, Daiki; Otsuki, Shunya; Sugimori, Shogo; Daicho, Hisayoshi; Iwaya, Motoaki; Takeuchi, Tetsuya; Kamiyama, Satoshi; Akasaki, Isamu

doi:10.1016/j.jcrysgro.2017.10.018

Cited by 15 publications

(25 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Details of growth conditions of the uid-a-GaN template and AlN buffer layer have been described elsewhere. 25,26) The threading dislocation density of the uid-a-GaN template was approximately 1.5 × 10 9 cm −2 . The 500 nm thick GaN layer was regrown on the uid-a-GaN templates using trimethylgallium (TMGa) and ammonia (NH 3 ) with H 2 as carrier gas.…”

Section: Experimental Methodsmentioning

confidence: 98%

“…In our previous study, uid-a-GaN with a low threading dislocation density using a patterned sapphire substrate (PSS) and sputtered AlN buffer layer was realized. [24][25][26] However, the typical a-plane multi quantum well (MQW) grown on a-GaN has some issues in terms of the surface morphology and the quality of the interface. In particular, growth pits appearing on the surface are remarkable.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Optical and structural characterization of GaInN/GaN multiple quantum wells grown on nonpolar a-plane GaN templates by metalorganic vapor phase epitaxy

Otsuki

Jinno

Daicho

et al. 2019

Jpn. J. Appl. Phys.

Self Cite

View full text Add to dashboard Cite

Typical multi quantum well (MQW) grown on nonpolar a-plane GaN templates shows many pits composed of several semipolar planes, and these pits emit at different wavelengths due to the variation of indium incorporations into the QW. In this study, a surface-recovery GaN layer and hightemperature grown barrier were introduced to improve the a-plane MQW quality. We succeeded in decreasing the pits prior to the MQW growth and improving the interfaces of MQW. The structural and optical properties of the MQW were significantly improved.

show abstract

Section: Experimental Methodsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Optical and structural characterization of GaInN/GaN multiple quantum wells grown on nonpolar a-plane GaN templates by metalorganic vapor phase epitaxy

Otsuki

Jinno

Daicho

et al. 2019

Jpn. J. Appl. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…23) Recently, a sputtered-AlN (sp-AlN) buffer layer was successfully demonstrated to improve the emission efficiency in AlGaN-based UV LEDs, electrical performance in GaInN-based blue LEDs, and crystalline quality of nonpolar a-plane GaN. [24][25][26] However, employing a sp-AlN buffer layer to overcome green-gap has not yet been reported.…”

Section: Introductionmentioning

confidence: 99%

Improvement of emission efficiency with a sputtered AlN buffer layer in GaInN-based green light-emitting diodes

Ishimoto¹,

Han²,

Yamamoto³

et al. 2019

Jpn. J. Appl. Phys.

Self Cite

View full text Add to dashboard Cite

We examined a sputtered AlN (sp-AlN) buffer layer to improve the emission efficiency of GaInN-based green LEDs. Both the electroluminescence and photoluminescence emission efficiencies are improved in a LED with a sp-AlN buffer layer compared to that with a conventional lowtemperature GaN buffer layer. To identify the origin of the improvements, we carried out the analysis including X-ray diffraction, surface morphology, initial nucleation growth, and temperature-dependent PL. Through analysis and consideration, we showed that the improvements are mainly caused by less strain and a lower degree of carrier localization in quantum wells (QWs), that is highly influenced by the grain diameter of the GaN island at initial growth. These results indicate that a sp-AlN buffer layer induces less compositional pulling that results in less strain and alloy fluctuation in QWs, simultaneously.

show abstract

“…[22][23][24] Since GaN epitaxial film grown on r-plane sapphire substrates is semi-polar, so strong built-in electric field inside the thin film can't be produced, and as a result luminous efficiency of the thin film is significantly improved. [25][26][27] In order to improve r-plane sapphire substrate processing efficiency, our team had done some studies. 17 For this study, the X-ray photo-emission spectroscopy (XPS) was applied to analyze chemical state of elements, z E-mail: 201521901031@stu.hebut.edu.cn; xhniu@hebut.edu.cn and one kind of component simple, higher chemical and stable alkaline sapphire slurry was investigated.…”

mentioning

confidence: 99%

Research on R-Plane Sapphire Substrate CMP Removal Rate Based on a New-Type Alkaline Slurry

Zhao

Niu

Yin

et al. 2018

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

Chemical mechanical polishing (CMP) is widely used as one of the most effective methods to achieve atomic-scale smooth surface. In order to investigate the mechanism of sapphire (α-Al 2 O 3 ) substrate CMP, the X-ray photo-emission spectroscopy (XPS) was applied to analyze the chemical state of elements. From XPS analysis it was demonstrated that AlO(OH) whose hardness was lower than α-Al 2 O 3 , existed only in c-plane sapphire after c-and r-plane polishing, so it's difficult to get high removal rate for r-plane CMP. But GaN epitaxial film grown on the r-plane sapphire substrate is semi-polar, and the luminous efficiency of the thin film is significantly improved. In order to improve r-plane sapphire substrate processing efficiency and accuracy, effects of pH regulator, KNO 3 concentration and surfactant concentration on r-plane sapphire CMP were studied. Higher removal rate of r-plane was obtained when KNO 3 concentration was 0.1 wt%, which was attributed to the particle size increase and new chemical reaction. But the removal rate decreased slightly due to the broadening of particle size distribution scope at higher ionic strengths. Anionic surfactant could improve removal rate and surface quality due to its good dispersion and stability to prevent nano-SiO 2 sol agglomeration. For r-plane sapphire, removal rate and surface roughness Sq can reach 1.43 um/h and 0.173 nm respectively, which provides guiding significance for the development of industrial sapphire ultra precise processing.

show abstract

Characterization and optimization of sputtered AlN buffer layer on r-plane sapphire substrate to improve the crystalline quality of nonpolar a-plane GaN

Cited by 15 publications

References 26 publications

Optical and structural characterization of GaInN/GaN multiple quantum wells grown on nonpolar a-plane GaN templates by metalorganic vapor phase epitaxy

Optical and structural characterization of GaInN/GaN multiple quantum wells grown on nonpolar a-plane GaN templates by metalorganic vapor phase epitaxy

Improvement of emission efficiency with a sputtered AlN buffer layer in GaInN-based green light-emitting diodes

Research on R-Plane Sapphire Substrate CMP Removal Rate Based on a New-Type Alkaline Slurry

Contact Info

Product

Resources

About