Title :
Low-resistance bandgap-engineered W/Si/sub 1-x/Ge/sub x//Si contacts
Author :
Chieh, Yuen-Shung ; Krusius, J. Peter ; Green, Dannellia ; Öztürk, Mehmet
Author_Institution :
Sch. of Electr. Eng., Cornell Univ., Ithaca, NY, USA
fDate :
7/1/1996 12:00:00 AM
Abstract :
Bandgap-engineered W/Si/sub 1-x/Ge/sub x//Si junctions (p/sup +/ and n/sup +/) with ultra-low contact resistivity and low leakage have been fabricated and characterized. The junctions are formed via outdiffusion from a selectively deposited Si/sub 0.7/Ge/sub 0.3/ layer which is implanted and annealed using RTA. The Si/sub 1-x/Ge/sub x/ layer can then be selectively thinned using NH/sub 4/OH/H/sub 2/O/sub 2//H/sub 2/O at 75/spl deg/C with little change in characteristics or left as-deposited. Leakage currents were better than 1.6/spl times/10/sup -9/ A/cm/sup 2/ (areal), 7.45/spl times/10/sup -12/ A/cm (peripheral) for p/sup +//n and 3.5/spl times/10/sup -10/ A/cm/sup 2/ (peripheral) for n/sup +//p. W contacts were formed using selective LPCVD on Si/sub 1-x/Ge/sub x/. A specific contact resistivity of better than 3.2/spl times/10/sup -8/ /spl Omega/ cm/sup 2/ for p/sup +//n and 2.2/spl times/10/sup -8/ /spl Omega/ cm/sup 2/ for n/sup +//p is demonstrated-an order of magnitude n/sup +/ better than current TiSi/sub 2/ technology. W/Si/sub 1-x/Ge/sub x//Si junctions show great potential for ULSI applications.
Keywords :
CVD coatings; Ge-Si alloys; contact resistance; energy gap; metallisation; semiconductor materials; tungsten; 75 C; RTA; ULSI; W-SiGe-Si; W/Si/sub 1-x/Ge/sub x//Si contact; annealing; bandgap engineering; fabrication; implantation; leakage current; outdiffusion; p/n junction; selective LPCVD; specific contact resistivity; thinning; Annealing; CMOS technology; Conductivity; Contacts; Hydrogen; Leakage current; Silicides; Substrates; Thermal stability; Ultra large scale integration;
Journal_Title :
Electron Device Letters, IEEE
