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Patterned growth of InGaN/GaN quantum wells on freestanding GaN grating by molecular beam epitaxy.

Wang Y, Hu F, Hane K - Nanoscale Res Lett (2011)

Bottom Line: Importantly, coalescences between two side facets are realized to generate epitaxial gratings with triangular section.Thin epitaxial gratings produce the promising photoluminescence performance.This work provides a feasible way for further GaN-based integrated optics devices by a combination of GaN micromachining and epitaxial growth on a GaN-on-silicon substrate.PACS81.05.Ea; 81.65.Cf; 81.15.Hi.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nanomechanics, Tohoku University, Sendai 980-8579, Japan. wyjjy@yahoo.com.

ABSTRACT
We report here the epitaxial growth of InGaN/GaN quantum wells on freestanding GaN gratings by molecular beam epitaxy (MBE). Various GaN gratings are defined by electron beam lithography and realized on GaN-on-silicon substrate by fast atom beam etching. Silicon substrate beneath GaN grating region is removed from the backside to form freestanding GaN gratings, and the patterned growth is subsequently performed on the prepared GaN template by MBE. The selective growth takes place with the assistance of nanoscale GaN gratings and depends on the grating period P and the grating width W. Importantly, coalescences between two side facets are realized to generate epitaxial gratings with triangular section. Thin epitaxial gratings produce the promising photoluminescence performance. This work provides a feasible way for further GaN-based integrated optics devices by a combination of GaN micromachining and epitaxial growth on a GaN-on-silicon substrate.PACS81.05.Ea; 81.65.Cf; 81.15.Hi.

No MeSH data available.


Schematical process of patterned growth on freestanding GaN grating by MBE.
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Figure 1: Schematical process of patterned growth on freestanding GaN grating by MBE.

Mentions: The proposed epitaxial growth of freestanding GaN grating is implemented on GaN-on-silicon substrate, consisting of 280 nm GaN layer, 450 nm AlxGa1 - xN layer (0.70 to approximately 0.20 Al mole fraction), 200-nm AlN buffer layer and 200-μm silicon handle layer. The fabrication process, described in detail elsewhere [17-19], is schematically illustrated in Figure 1. Nanoscale gratings are patterned in ZEP520A resist using EB lithography, and the resist structures act as a mask for FAB etching of GaN (steps a-b). The Cl2 gas is used as the process gas, and the etching depth is about 200 nm (step c). Then the residual EB resist is stripped and the processed device layer is protected by thick photoresist (step d). Silicon substrate beneath the GaN grating region is patterned from backside and etched down to the AlN layer by DRIE, where the AlN layer serves as a definite etch stop (step e). The freestanding GaN gratings are generated by removing the residual photoresist and cleaned for the epitaxial growth (step f). The epitaxial growth is conducted on the processed GaN template by MBE with radio frequency nitrogen plasma as gas source (step g). The epitaxial films with a designed thickness of approximately 420 nm incorporate approximately 140-nm low-temperature buffer layer, approximately 200-nm high-temperature GaN layer, six-pair 3-nm InGaN/9-nm GaN QWs layer and 10-nm GaN top layer. The growth process is described below.


Patterned growth of InGaN/GaN quantum wells on freestanding GaN grating by molecular beam epitaxy.

Wang Y, Hu F, Hane K - Nanoscale Res Lett (2011)

Schematical process of patterned growth on freestanding GaN grating by MBE.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211162&req=5

Figure 1: Schematical process of patterned growth on freestanding GaN grating by MBE.
Mentions: The proposed epitaxial growth of freestanding GaN grating is implemented on GaN-on-silicon substrate, consisting of 280 nm GaN layer, 450 nm AlxGa1 - xN layer (0.70 to approximately 0.20 Al mole fraction), 200-nm AlN buffer layer and 200-μm silicon handle layer. The fabrication process, described in detail elsewhere [17-19], is schematically illustrated in Figure 1. Nanoscale gratings are patterned in ZEP520A resist using EB lithography, and the resist structures act as a mask for FAB etching of GaN (steps a-b). The Cl2 gas is used as the process gas, and the etching depth is about 200 nm (step c). Then the residual EB resist is stripped and the processed device layer is protected by thick photoresist (step d). Silicon substrate beneath the GaN grating region is patterned from backside and etched down to the AlN layer by DRIE, where the AlN layer serves as a definite etch stop (step e). The freestanding GaN gratings are generated by removing the residual photoresist and cleaned for the epitaxial growth (step f). The epitaxial growth is conducted on the processed GaN template by MBE with radio frequency nitrogen plasma as gas source (step g). The epitaxial films with a designed thickness of approximately 420 nm incorporate approximately 140-nm low-temperature buffer layer, approximately 200-nm high-temperature GaN layer, six-pair 3-nm InGaN/9-nm GaN QWs layer and 10-nm GaN top layer. The growth process is described below.

Bottom Line: Importantly, coalescences between two side facets are realized to generate epitaxial gratings with triangular section.Thin epitaxial gratings produce the promising photoluminescence performance.This work provides a feasible way for further GaN-based integrated optics devices by a combination of GaN micromachining and epitaxial growth on a GaN-on-silicon substrate.PACS81.05.Ea; 81.65.Cf; 81.15.Hi.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nanomechanics, Tohoku University, Sendai 980-8579, Japan. wyjjy@yahoo.com.

ABSTRACT
We report here the epitaxial growth of InGaN/GaN quantum wells on freestanding GaN gratings by molecular beam epitaxy (MBE). Various GaN gratings are defined by electron beam lithography and realized on GaN-on-silicon substrate by fast atom beam etching. Silicon substrate beneath GaN grating region is removed from the backside to form freestanding GaN gratings, and the patterned growth is subsequently performed on the prepared GaN template by MBE. The selective growth takes place with the assistance of nanoscale GaN gratings and depends on the grating period P and the grating width W. Importantly, coalescences between two side facets are realized to generate epitaxial gratings with triangular section. Thin epitaxial gratings produce the promising photoluminescence performance. This work provides a feasible way for further GaN-based integrated optics devices by a combination of GaN micromachining and epitaxial growth on a GaN-on-silicon substrate.PACS81.05.Ea; 81.65.Cf; 81.15.Hi.

No MeSH data available.