Ultra low density of interfacial traps with mixed thermal and plasma enhanced ALD of high-κ gate dielectrics

摘要: Anomalous growth per cycle was observed using in situ ellipsometry during the initial cycles of plasma enhanced atomic layer deposition (ALD) high-κ dielectrics, while thermal these oxides exhibited linear cycle. The anomalous attributed to oxidation substrate by oxygen. Thermally grown films have a lower capacitance density and higher leakage current but interfacial traps compared films. For films, is dominated direct tunnelling trap assisted seems be dominant thermally Initiating oxide with then switching process protects surface from oxygen lowers (Dit). Starting ten ZrO2 enhances decreasing Dit. lowest value Dit obtained twenty (1.8 × 1010 cm−2 eV−1). mid-gap reduces systematically an increasing number ALD cycles. Furthermore, frequency dispersion accumulation reduced up twenty.