Dry etching and implantation characteristics of III-N alloys

• Published in: Materials science & engineering. B, Solid-state materials for advanced technology Solid-state materials for advanced technology, 1995-05, Vol.31 (3), p.309-317
• Main Authors: Pearton, S.J., Vartuli, C.B., Shul, R.J., Zolper, J.C.
• Format: Article
• Language: English
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; III–V nitrides; Ion implantation; Materials science; Photonics; Physics; Plasma etching; Surface treatments
• ISSN: 0921-5107; 1873-4944
• DOI: 10.1016/0921-5107(94)01154-0

The wide-gap nitrides GaN, AIN and InN and their ternary alloys are attracting interest for blue-UV emitters, high temperature electronics and as passivation films for other semiconductors. We review the dry etching chemistries that are found to provide smooth anisotropic pattern transfer in these materials, namely Cl 2H 2, BCl 3 or CH 4H 2 for Al x Ga 1− x N alloys and CH 4H 2 for In x Ga 1− x N alloys. Microwave enhancement of the discharge is useful for increasing the etch rate at fixed d.c. self-bias. Ar + ion milling rates for the nitrides are typically a factor of 2 lower than for conventional III-Vs such as GaAs and InP. Implant isolation of In x Ga 1− x N shows similar characteristics to GaAs, namely a several orders of magnitude increase in resistance after implantation with moderate doses of F + or O +, followed by a further increase with annealing temperature up to about 500°C as hopping conduction is decreased. Minimal diffusion of most implanted dopants is found up to annealing temperatures of 800°C. Prospects for other process modules, especially wet chemical etching and ohmic contacts, will be discussed.