Coherent light generators – Particular resonant cavity – Distributed feedback
Reexamination Certificate
2001-11-29
2004-08-10
Wong, Don (Department: 2828)
Coherent light generators
Particular resonant cavity
Distributed feedback
C372S043010
Reexamination Certificate
active
06775314
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention describes a Distributed Bragg Reflector and method for making utilizing multiple layers of AlGaN/GaN and, more particularly, utilizing an interlayer to achieve sufficient reflectivity for a vertical cavity laser.
The growth of epitaxial distributed Bragg reflectors (DBRs) with high crystalline quality is important in the successful development of infrared and red vertical-cavity surface-emitting lasers (VCSELs). The development of III-Nitride-based VCSELs for short-wavelength (visible and ultraviolet) applications requires the preparation of crack-free, highly reflective (that is, high R) (Al,Ga)N/GaN DBRs. Difficulties arise in the preparation of crack-free highly reflective (Al,Ga)N/GaN DBRs owing to the large lattice mismatch between GaN and AlN (approximately 2.4%).
Because multiple passes of optical waves are required in VCSELs due to a short cavity (gain) length, highly reflective mirrors (typically R>99%) are required for low threshold operation. The low contrast in index of refraction between AlN and GaN (and thus the ternary alloys) necessitates the use of a large number of pairs of mirrors to achieve such reflectivities. Someya and Arakawa (Someya, T., and Arakawa, Y., Appl. Phys. Lett., 1998, 73, 3653-3655) reported the crack-free growth of a 35-pair Al
0.34
Ga
0.66
N/GaN DBR with reflectivity up to 96% at 390 nm. It was emphasized in that work that the thickness of the (high temperature-grown) GaN layer must be restricted to 0.4 &mgr;m or less to avoid sample cracking. Langer et al. (Langer, R., Barski, A., Simon, J., Pelekanos, N. T., Konovalov, O., Andre, R., and Dang, L. S., Appl. Phys. Lett., 1999, 74, 3610-3612) reported a maximum reflectivity of 93% at 473 nm with 30 pairs of Al
0.4l
Ga
0.59
N/GaN DBRs. Krestnikov et al. (Krestnikov, I., Lundin, W., Sakharov, A., Semenov, V., Usikov, A., Tsatsul'nikov, A., Alferov, Zh., Ledentsov, N., Hoffman, A., and Bimberg, D., Appl. Phys. Lett., 1999, 75, 1192-1194) employed a 1.1 &mgr;m Al
0.08
Ga
0.92
N template on sapphire for stress compensation and showed a reflectivity of 96% at 401 nm with 37 pairs of Al
0.15
Ga
0.085
N/GaN DBR mirrors. More recently, Ng et al. (Ng. H., Moustakas, T., and Chu, S., Appl. Phys. Lett., 2000, 76, 2818-2820) explored DBR mirrors consisting of binary AlN and GaN for increased contrast in the index of refraction. A 99% reflectivity at 467 nm was obtained with one specific structure that employed approximately 20 to 25 pairs of DBR mirrors. A network of cracks was observed which was attributed to the large tensile stress between the two binary compounds. Kim (U.S. Pat. No. 6,306,672, issued on Oct. 23, 2001) describes the formation of DBRs for use in a VCSEL diode where low refractive index air layers are incorporated into the DBR to achieve desired reflectivity. Etching is used to form air layers out of conventional AlGaN or GaN material. These DBRs are utilized in forming a VCSEL diode. Waldrip et al. (Waldrip, K. E., Han, J., Figiel, J. J., Zhou, H., Makarona, E. and Nurmikko, A. V., Appl. Physics Letters, 2001, 78, 22, 3205-3207; incorporated herein by reference) describe the use of interlayers in DBR structures to address the mismatch of the AlGaN/GaN layers and achieve high reflectivity DBR structures without cracks.
REFERENCES:
patent: 4205329 (1980-05-01), Dingle et al.
patent: 4261771 (1981-04-01), Dingle et al.
patent: 5838707 (1998-11-01), Ramdani et al.
patent: 5985687 (1999-11-01), Bowers et al.
patent: 6194744 (2001-02-01), Udagawa et al.
patent: 6229834 (2001-05-01), Nisitani et al.
patent: 6285698 (2001-09-01), Romano et al.
patent: 6306672 (2001-10-01), Kim
patent: 6562207 (2003-05-01), Kano et al.
patent: 6576932 (2003-06-01), Khare et al.
patent: 2001/0035531 (2001-11-01), Kano et al.
patent: 2001/0048112 (2001-12-01), Koide et al.
patent: 2002/0036295 (2002-03-01), Nunoue et al.
patent: 2003/0123829 (2003-07-01), Taylor
Waldrip, K. Han., J., Figiel, J., Zhou, H., Makarona, E., and Nurmikko, A., “Stress engineering during metalorganic chemical vapor deposition of AIGaN/GaN distributed Bragg reflectors,” Appl. Phys. Lett., 2001, 78, 21, 3205-3207.
Ng, H., Moustakas, T., and Chu, S., “High reflectivity and broad bandwidth AIN/GaN distributed Bragg reflectors grown by molecular-beam epitaxy,” Appl. Phys. Lett., 2000, 76, 20, 2818-2820.
Kerstnikov, I., Lundin, W., Sakharov, A., Semenov, V., Usikov, A., Tsatsul'nikov, A., and Alferov, Zh., Ledentsov, N., Hoffmann, A., and Bimberg, D., “Room-temperature photopumped inGaN/GaN/AIGaN vertical-cavity surface-emitting laser,” Appl. Phys. Lett., 1999, 75, 9, 1192-1194.
Langer, R., Barski, A., Simon, J., Pelekanos, N. Konovalov, O., Andre, R., and Dang, L., “High reflectivity GaN/GaAIN Bragg mirrors at blue/green wavelengths grown by molecular beam epitaxy,” Appl. Phys. Lett., 1999, 74, 24, 3610-3612.
Zhou, H., Diagne, M., Makarona, E., Nurmikko, A., Han, J., Waldrip, K., Figiel, J., “Near ultraviolet optically pumped vertical cavity laser,” Elec. Lett., 2000, 36, 21.
Someya, T., and Arakawa, Y., “Highly reflective GaN/AL0.34Ga0.66N quarter-wave reflectors grown by metal organic chemical vapor deposition,” Appl. Phys. Lett., 1998, 73, 25, 3653-3655.
Benamara, M., Liliental-Weber, Z., Kellermann, S., Swider, W., Washburn, J., Mazur, J., and Bourret-Courchesne, E., “Study of high-quality GaN grown by OMVPE using an intermediate layer,” J. Crys. Growth, 2000, 218, 447-450.
Amano, H., Iwaya, M., Hayashi, N., Kashima, T., Katsuragawa, M., Takeuchi, T., Wetzel, C. and Akasaki, I., “Improvement of crystalline quality of group III nitrides on sapphire using low temperature interlayers,” MRS Internet J. Nitr. Semicond. Res. 4S1, 1999, G10.1.
Han Jung
Lee Stephen R.
Waldrip Karen E.
Ashby Carol I
Klavetter Elmer A
Nguyen Tuan N.
Sandia Corporation
Wong Don
LandOfFree
Distributed bragg reflector using AIGaN/GaN does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Distributed bragg reflector using AIGaN/GaN, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Distributed bragg reflector using AIGaN/GaN will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3340528