Deep levels associated with dislocation annihilation by Al pre-seeding and silicon delta doping in GaN grown on Si(111) substrates

Autor: Lianshan Wang, S. Y. Chow, K. Y. Zang, Soo Jin Chua, Chew Beng Soh
Rok vydání: 2008
Předmět:
Zdroj: physica status solidi (a). 205:266-270
ISSN: 1862-6319
1862-6300
Popis: The introduction of Si burst during the growth of GaN film on Si(111) substrate by MOCVD formed a Six Ny layer which leads to an effective reduction in the density of screw dislocations. The reduction is associated with bending of screw dislocations to form a square dislocation loop when neighbouring dislocations with opposite Burger's vector paired up. The concentration of electron traps Ec–Et ∼0.17–0.26 eV which is associated with screw dislocations is substantially reduced and a kink is left at the silicon rich position. The mixed-edge dislocation, however, is not annihilated by the Six Ny layer. Addition of TMAl burst for the AlN growth leads to a substantial reduction in trap concentration associated with the nitrogen vacancies, VN, and antisite of nitrogen, NAl, at Ec–Et ∼0.10 eV and Ec–Et ∼ 0.60 eV respectively. This improves the quality of the subsequent layer of HT-GaN grown and is useful for device fabrication. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Databáze: OpenAIRE