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

Paper EM-MoA2
High Breakdown Voltage Au/Pt/GaN Schottky Diode

Monday, October 25, 1999, 2:20 pm, Room 608

Session: Nitride Processing and Characterization
Presenter: G. Dang, University of Florida
Authors: J.I. Chyi, National Central University, Taiwan
J.M. Lee, National Central University, Taiwan
C.C. Chuo, National Central University, Taiwan
G.C. Chi, National Central University, Taiwan
G. Dang, University of Florida
A.P. Zhang, University of Florida
X.A. Cao, University of Florida
M.M. Mshewa, University of Florida
F. Ren, University of Florida
S.J. Pearton, University of Florida
S.N.G. Chu, Bell Labs, Lucent Technologies
W.G. Wilson, Charles Evans and Associates
Correspondent: Click to Email
Au/Pt/GaN Schottky diode rectifiers with a reverse breakdown voltage of -325V were demonstrated. The GaN sample studied in this work was grown on c-plane sapphire by low-pressure metalorganic chemical vapor deposition in a horizontal reactor. Ammonia (NH@sub 3@), trimethylgallium (TMG), and silane (SiH@sub 4@) were used as precursors and dopants, respectively. Two-step growth method was used to obtain GaN films with smooth surface. A low temperature GaN nucleation layer of about 220 nm was first grown at 460 °C after the substrate was heated at 1050 °C in hydrogen ambient for 10 minutes. Then the substrate temperature was raised to 1050 °C for the growth of the 1 µm-thick Si-doped (3E18 cm@super -3@) and 5 µm-thick undoped GaN layers. From the diode C-V measurement, the background doping of the undoped GaN is 1E16 cm@super -3@. The growth rate of high temperature GaN was 1.5 µm/hr, while that for the nucleation layer was about 0.3 µm/hr. TEM cross-sectional view of the sample shows that the growth interruption during the nitride growth reduces the dislocation density significantly. From the SIMS analysis, the concentrations of carbon, oxygen and hydrogen in the undoped layer are 2E17, 3E17, and 3E18, respectively. AFM roughness was around 1nm over 10x10 µm@super 2@.