Amorphous High k Dielectric Bi_(1-X-Y)Ti_XSi_YO_Z Thin Films by ALD

摘要

We report a new class of high k dielectrics based on ternary amorphous metal oxide, Bi_(1-x-y)Ti_xSi_yO_z (BTSO, x = 0.4, y = 0.2). BTSO films grown by atomic layer deposition (ALD) have a dielectric constant of 55-64, which is the highest value reported among amorphous dielectric films. Leakage current density of the films is on the order of 10~(-8) A/cm~2 at 1 V with dielectric breakdown strength of 0.6-1.6 MV/cm. Thickness and compositional uniformities on hole structures with a high aspect ratio (7) are also investigated with Bi_2Ti_2O_7 films without Si, of which conformality is excellent with respect to both thickness and composition.