AVS 46th International Symposium
    Electronic Materials and Processing Division Monday Sessions
       Session EM-MoA

Paper EM-MoA5
Schottky Diode Measurements of Dry Etch Damage in n- and p-type GaN

Monday, October 25, 1999, 3:20 pm, Room 608

Session: Nitride Processing and Characterization
Presenter: X.A. Cao, University of Florida
Authors: X.A. Cao, University of Florida
A.P. Zhang, University of Florida
G. Dang, University of Florida
F. Ren, University of Florida
S.J. Pearton, University of Florida
R.J. Shul, Sandia National Laboratories
L. Zhang, Sandia National Laboratories
Correspondent: Click to Email
N- and p- type GaN was exposed to Inductively Coupled Plasma (ICP)of N@sub 2@, Ar or H@sub 2@, as a function of high density source power(0-1400 W) and rf chuck power(20-250 W). For n-GaN there was a strong reduction in diode reverse breakdown voltage and an increase in forward and reverse currents, while for p-GaN the reverse breakdown increased. These results are consistent with creation of point defects with shallow donor nature that increase the conductivity of initial n-GaN or decrease the conductivity of initially p-GaN. Annealing at ~750 @super o@C under N@sub 2@ or removal of 500-600 Å of the surface essentially recovered the electrical properties of the plasma exposed GaN. For completed n-type mesa diode structures exposed to ICP Ar or Cl@sub 2@/Ar discharges, the low-bias forward currents increased by several orders of magnitude. The exposed surfaces became N@sub 2@-deficient in all cases, and both UV-ozone oxidation followed by dissolution of the oxide and annealing in N@sub 2@ were examined for restoration of the diode properties.