Effects of Interface Structure on the Electrical Characteristics of PtSi-Si Schottky Barrier Contacts

The properties of PtSi-Si Schottky barrier contacts formed by a new technique employing multilayer metallization are compared with those of contacts prepared by the conventional single-layer metallization method. The multilayer technique permits the formation of very shallow contacts without any limitation being placed on the thickness of the PtSi layer. For a PtSi layer of given thickness the PtSi-Si contact interface obtained by this technique is more uniform than the interface formed by annealing a single layer of platinum on silicon. The interfacial uniformity is independent of PtSi thickness for shallow PtSi-Si contacts produced by the multilayer technique, while for conventional contacts the uniformity decreases with increasing PtSi thickness. Large-area (9.4 × 10−3 cm2) diodes utilizing shallow PtSi-Si contacts about 200 Å deep have been fabricated without guard rings. These diodes exhibit near-ideal forward current-voltage characteristics, low reverse leakage currents (less than 5 nA at −10 V) and high breakdown voltages (over −90 V). These characteristics are superior to those of diodes using conventional PtSi-Si contacts.