Title :
NiZnAl-based p-type ohmic contacts on AlGaAs/InGaAs heterostructures
Author :
Abrokwah, J.K. ; Huang, J.H. ; Baker, J. ; Polito, T. ; Ooms, W.
Author_Institution :
Motorola Inc., Tempe, AZ, USA
fDate :
6/1/1993 12:00:00 AM
Abstract :
p-type ohmic contacts based on Ni/Zn/Al/TiWN metallization were evaluated for application to self-aligned p-channel heterostructure FETs. Low-resistance, stable ohmic contacts were achieved on Alx Ga1-xAs/InGaAs heterostructures with aluminum composition (x) as high as 0.75. Following short-term annealing of 30 s in the temperature range of 500°C to 600°C, contact resistances less than 0.6 Ω-mm and specific resistivities under 5×10-6 Ω-cm2 were achieved. Further anneal at 500°C for 10 min resulted in a minimum contact resistance of 0.06 Ω-mm and a specific resistivity of 3.2×10-8 Ω-cm2. Contact morphology was mirror-smooth and specular and the contacts were found to be stable at 500°C for anneal times as long as 40 min, with contact resistance remaining below 1 Ω-mm
Keywords :
III-V semiconductors; aluminium; aluminium compounds; annealing; contact resistance; gallium arsenide; indium compounds; insulated gate field effect transistors; metallisation; nickel; ohmic contacts; semiconductor-metal boundaries; titanium alloys; tungsten alloys; zinc; 10 min; 30 s; 500 to 600 degC; Al0.75Ga0.25As-In0.2Ga0.8 As-GaAs; Ni-Zn-Al-TiWN metallization; contact morphology; contact resistances; p-type ohmic contacts; self-aligned p-channel heterostructure FETs; short-term annealing; specific resistivities; Aluminum; Annealing; Conductivity; Contact resistance; HEMTs; Indium gallium arsenide; MODFETs; Metallization; Ohmic contacts; Zinc;
Journal_Title :
Electron Devices, IEEE Transactions on
