Improved optical activation of ion-implanted Zn acceptors in GaN by annealing under N 2 overpressure
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Internet Journal o f
Nitride S emiconductor Research
Volume 2, Article 4
Improved optical activation of ion-implanted Zn acceptors in GaN by annealing under N2 overpressure A. Pelzmann Abteilung Optoelektronik, Universität Ulm S. Strite IBM Research Division, Zurich Research Laboratory A. Dommann Neu-Technikum Buchs C. Kirchner, Markus Kamp , K. J. Ebeling Abteilung Optoelektronik, Universität Ulm A. Nazzal IBM Almaden Research Center, 650 Harry Road, San Jose CA 95120-6099 USA This article was received on December 30, 1996 and accepted on January 24, 1997.
Abstract We investigated the properties of ion-implanted GaN:Zn annealed under various conditions using photoluminescence (PL) and high resolution x-ray diffraction (HRXRD). Epitaxial GaN/sapphire of high optical quality was ion-implanted with a 1013 cm-2 dose of Zn+ ions at 200 keV. The sample was capped with 200 Å of SiNx and then diced into numerous pieces which were annealed under varied conditions in an attempt to optically activate the Zn. Annealing was performed in a tube furnace under flowing N2, an atmospheric pressure MOCVD reactor under flowing NH3 or N2, and under an N2 overpressure of 190 atm. The observed improvement in the optical quality of GaN:Zn annealed under N2 overpressure yields further insights into the trade-off between defect annealing and N loss from the GaN crystal.
1. Introduction 1.1. Purpose of the Investigation Ion-implantation is widely used in semiconductor device technology to locally alter the electrical properties of materials, e.g. for doping or isolation. GaN device technology is rapidly advancing towards maturity. For electronic device applications, it is likely that techniques of optimally ion-implanting and activating impurities in GaN will need to be developed. GaN LEDs can luminescence in any of the visible colors dependent on the dopant introduced [1]. If it is possible to realize good optical quality implanted GaN, LEDs and electronic devices could benefit from dopants incompatible with epitaxial growth processes. It would also be possible to fabricate monolithic multicolor LED arrays [2] [3] by selective area implantation of different color centers. Such arrays could be useful for color printing, or as tiny, bright, high information content displays. Typically ion-implantation introduces damage to the crystal which must be annealed out. This procedure is routine in semiconductors such as Si in which crystal repair occurs at temperatures well below those causing decomposition. In Downloaded from https://www.cambridge.org/core. IP address: 212.119.45.80, on 30 Aug 2020 at 20:55:59, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/S1092578300001307
y p p g p the case of compound semiconductors, rapid thermal annealing (RTA) at temperatures near or above the decomposition temperature is often preferred, usually in the presence of an overpressure of a stabilizing gas, such as arsenic for GaAs or phosphorus for InP, to limit decomposition. The sit
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