Open AccessLow‐Resistance, High‐Transparency, and Thermally Stable Ohmic Contacts on p‐Type GaN Using Ru and Ir
Author(s) -
Won Jang Ho,
Min Jeon Chang,
Lee JongLam
Publication year - 2002
Publication title -
physica status solidi (c)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 46
eISSN - 1610-1642
pISSN - 1610-1634
DOI - 10.1002/pssc.200390030
Subject(s) - ohmic contact , materials science , contact resistance , non blocking i/o , annealing (glass) , electrical resistivity and conductivity , schottky barrier , thermal stability , optoelectronics , transmittance , optical transparency , sheet resistance , layer (electronics) , metallurgy , composite material , chemistry , electrical engineering , biochemistry , organic chemistry , diode , engineering , catalysis
Low‐resistance, high‐transparency, and thermally stable ohmic contacts on p‐type GaN were achieved using Ru‐ and Ir‐based metallization through oxidation annealing. A contact resistivity of ∼4 × 10 —5 Ωcm 2 and a high light transmittance of ∼85% were obtained from oxidized Ru (50 Å)/Ni (50 Å) and Ir (50 Å)/Ni (50 Å) contacts. The formation of a RuO 2 (or IrO 2 )/p‐GaN contact reduced the effective Schottky barrier height for hole injection and a NiO layer at the surface suppressed the outdiffusion of free Ga and N atoms, resulting in a reduction of the contact resistivity. The fully oxidized contact structure of NiO/RuO 2 (or IrO 2 )/p‐GaN enhanced the light transmission and the thermal stability simultaneously.