LIGHT-EMITTING-DIODES AS A MONITOR TO STUDY P-TYPE DOPING OF GAN-BASED HETEROSTRUCTURES GROWN BY MOVPE

The group-III nitrides are an interesting material system for applicat ions in the blue spectral region and for high-power and high-temperatu re devices. P-type doping in the metalorganic vapour-phase growth proc ess: however, suffers from the material's high-background donor concen tration. Hydrogen passivation furthermore decreases the number of acti vated accepters [N.W. Johnson, W, Gotz, J. Neugebauer, C.G. van de Wal le, Mater. Res. Sec. Symp. Proc. 395 (1996) 723: A. Bosin, V. Fiorenti ni, Mater. Res. Sec. Symp. Proc. 395 (1996) 503] [1,2]. Thermal treatm ent was found to increase the amount of activated accepters [S.J, Pear ton, S. Bendi, K.S. Jones, V. Krishnamoorthy, R.G. Wilson, F. Ren, R,F . Karlicek, R.A. Stall, Appl, Phys. Lett, 69 (1996) 1879; Y. Li, Y. Lu , H. Shen, M. Wraback, C.Y. Hwang, M. Schurman, W. Mayo, T. Salagaj, R .A. Stall, Mater. Res. Sec. Symp. Proc.395 (1996) 369] [3,4]. We have investigated the influences of thermal treatment process steps on the electrical and optical properties of Mg-doped single layers and used t he results to fabricate AlGaN/GaN heterostructure LED layers. A simple test structure was employed to assess the electro-optical properties of the LED structures. (C) 1998 Elsevier Science B.V. All rights reser ved.