Selection of rare earth silicates for highly scaled gate dielectrics

SrO capping effect for La2O3/Ce-silicate gate dielectrics

“…From fitting with CVC program [16], a small EOT of 0.58 nm was obtained by split-CV measurement. As the EOT of the FET without SrO capping was found to be 0.60 nm, the combination of Ce-silicate layer with SrO capping technique is effective for EOT scaling [17]. Fig.…”

Leakage current and structural analysis of annealed HfO2/La2O3 and CeO2/La2O3 dielectric stacks: A nanoscopic study

“…1-3 CeO 2 is another promising HK dielectric, especially for future CMOS technology nodes, considering its good dielectric strength (j $ 20-25), large bandgap (E g $ 5.5 eV), high thermal and chemical stability, and low lattice mismatch with silicon substrates. 4,5 Both HfO 2 and CeO 2 are studied in this work, as well as the addition of lanthanum (La) into the gate dielectric stack.…”

“…[4][5][6][7][8] The lanthanum oxide (La 2 O 3 ) itself has good dielectric properties (j ¼ 25-30, bandgap (E g ) $ 5.5 eV), but it is also significant to note that lanthanum forms a La-silicate interfacial layer (IL) (j $ 14) on Si, after high-temperature annealing up to 1000 C. [9][10][11] Thus, direct deposition is possible without the need of IL of SiO (x<2) , enabling more aggressive scaling of the equivalent oxide thickness (EOT). La 2 O 3 is chemically unstable in ambient air and is rapidly transformed (in a few hours) to LaO(OH) or La(OH) 3 , leading to layer swelling.…”

Subthreshold Characteristics of MOS Transistors With $ \hbox{CeO}_{2}/\hbox{La}_{2}\hbox{O}_{3}$ Stacked Gate Dielectric

“…Particularly, lanthanum has much large value (more negative) of oxygen chemical potential, and its oxide was found to have large amount of oxygen vacancies [3], [4]. It has been reported recently that the multivalent cerium can be used to control the equilibrium oxygen chemical potential of La 2 O 3 films [5], [6]. Cerium oxides (CeO 2 and Ce 2 O 3 ) can either absorb or release oxygen.…”