Title :
The role of Ru in improving Au-Be ohmic contacts to p-type InP
Author :
Malina, V. ; Moro, L.
Author_Institution :
Inst. of Radio Eng. & Electron., Czechoslovak Acad. of Sci., Prague, Czech Republic
Abstract :
In this work, an innovated Au-Be/Ru/Au vacuum-deposited contact system to moderately doped p-type InP has been proposed, where the thickness of Au-Be contact layer was minimized and a new, more effective diffusion barrier of Ru was incorporated between the Au-Be and a thick Au top layer. After the alloying at 425°C for 2 minutes in pure H 2 gas, the specific contact resistance dropped to a minimum value of 2×10-4 ohm.cm2 (for an acceptor concentration of about 3×1018 cm-3) and the contacts became perfectly ohmic. When subjected to an aging test at 280°C for 50 hours in N2 atmosphere, such ohmic contacts, originally alloyed at 425°C, exhibited a remarkable electrical and metallurgical stability. SNMS in-depth profile measurements confirmed that the Ru layer is an excellent barrier against the migration of Au into the semiconductor and it also suppresses the out-diffusion of In and P from the semiconductor
Keywords :
III-V semiconductors; ageing; beryllium alloys; contact resistance; diffusion barriers; gold; gold alloys; mass spectra; ohmic contacts; ruthenium; semiconductor-metal boundaries; vacuum deposited coatings; 2 min; 280 degC; 425 degC; 50 hour; Au-Be ohmic contacts; Au-Be/Ru/Au vacuum-deposited contact system; AuBe-Ru-Au; H2; InP; N2; SNMS in-depth profile measurements; alloying; contact resistance; diffusion barrier; electrical stability; metallurgical stability; out-diffusion; p-type InP; Aging; Alloying; Atmosphere; Contact resistance; Gold; Indium phosphide; Ohmic contacts; Stability; Testing; Vacuum systems;
Conference_Titel :
Indium Phosphide and Related Materials, 1996. IPRM '96., Eighth International Conference on
Conference_Location :
Schwabisch-Gmund
Print_ISBN :
0-7803-3283-0
DOI :
10.1109/ICIPRM.1996.492049
