Materials Science Forum, Vol.338-3, 1013-1016, 2000
Searching for device processing compatible ohmic contacts to implanted p-type 4H-SiC
To search for device processing compatible ohmic contacts to mid-10(20)cm(-3) Al+C coimplanted p-type 4H-SiC, Ti and layered Ti, Al and layered Al, Pd and layered Pd metal systems have been studied. Aluminum based contacts give the lowest specific contact resistance with a median value of 4.7x10(-5)Omega .cm(2). However, Al requires a high annealing temperature and is easily oxidized, making it difficult to get a device processing compatible Al contact. Efforts have been made to see if any metal over-layer could be used to solve the problem and the results are reported. Titanium covered by W has high 10(-4)Omega .cm(2) specific contact resistance. When covered by Al, Ti/Al contact gives a better specific contact resistance of 1.4x10(-4) Omega .cm(2). But Al tends to get oxidized during annealing in a conventional annealing furnace. Palladium is attractive because of its low annealing temperature and high resistance to oxidation with a reasonably good specific contact resistance of high 10(-5)Omega .cm(2). Pd and layered Pd contacts may be further improved to provide device processing compatible ohmic contacts to p-type 4H-SiC.