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High Density Plasma Etching Damage Effects on Contacts to n-GaN

Published online by Cambridge University Press:  17 March 2011

Rajwinder Singh
Affiliation:
Boston University, Department of Electrical & Computer Engineering, & Photonics Center 8 St. Mary's Street Boston MA 02215, USA
C. R. Eddy Jr
Affiliation:
ceddy@bu.edu
T.D. Moustakas
Affiliation:
Boston University, Department of Electrical & Computer Engineering, & Photonics Center 8 St. Mary's Street Boston MA 02215, USA
H.M. Ng
Affiliation:
Bell Laboratories, Lucent Technologies, 600 Mountain Avenue, Room 6H-424 Murray Hill 07974 NJ, USA
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Abstract

The effects of inductively-coupled plasma etching on the quality of ohmic contacts to etched n- GaN are reported. A high density chlorine plasma and a range of rf bias power levels (incident ion energies) are employed to etch n-GaN films with varying doping levels. Resulting plasma damage degrades contact ohmicity in all cases examined. At moderate levels of rf bias power the extent of this degradation for nitride layers with lower doping levels (mid-1017 cm−3) is similar to the degradation for nitride layers with higher doping levels. With increased rf bias, the degradation becomes more severe in films with higher carrier concentration. Annealing at 700 °C rapidly improves the contact quality. Studies of cumulative annealing time, up to 160 seconds, show that the improvement in contact quality takes place within the first twenty seconds of annealing.

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

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References

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