MIJ-NSR Vol. 8, Art. 5, Jae-Hoon Lee et al.

Growth of Semi-insulating GaN Layer by Controlling Size of Nucleation Sites for SAW Device Applications

Jae-Hoon Lee, Myoung-Bok Lee, Sung-Ho Hahm, Yong-Hyun Lee, Jung-Hee Lee
School of Electronic Engineering and Computer Science, Kyungpook National University, Daegu 702-701, Korea

Young- Ho Bae
Division of Information and Electronics, Uiduk University, Gyeongju 780-910, Korea

Hyun Kyung Cho
Department of Metallurgical Engineering, Dong-A University, Busan, 604-717, Korea

This article was received on Friday, July 4, 2003 and accepted on Wednesday, August 13, 2003.

Abstract

Semi-insulating undoped GaN films were grown based on controlling the size of the nucleation sites through a special two-step growth method: First, 16 nm LT-GaN was annealed at 950 ° with a ramping time of 4 min, then the GaN was grown at this temperature for 1 min. Second, the growth temperature was increased to 1020° with a ramping time of 2 min and the GaN layer finally grown at 1020 ° for 40 min. The film grown by this sequence exhibited sheet resistance of up to 10⁹

/sq with mirror-like surface morphology. By slow ramping to 950° in the initial phase of growth, smaller grain sizes and higher nuclei densities were formed and the columnar growth mode along the c direction was dominant. The observation of higher resistance in two-step growth is believed due to the increased misorientation of nuclei when the growth proceeds during temperature ramping to 1020°. The fabricated saw filter on semi-insulating GaN exhibited a high velocity of 5342 m/s at center frequencies of 133.57 MHz and an electromechanical coupling coefficient(k²) of about 0.763 %, which was enhanced due to the improvement of surface morphology with high sheet resistance by the two- step ramping technique.

Outline

Introduction

Experiments

Results and Discussion

Conclusions

Acknowledgments

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Cite this article as: MRS Internet J. Nitride Semicond. Res. 8, 5(2003).

last updated Wednesday, December 8, 2004 5:02:39 PM.