Structure and Electrical Properties of Thin Ta₂O₅ Deposited on Metal Electrodes

Abstract

The structure and electrical properties of chemical vapor deposition (CVD)-Ta2O5 thin films on Pt, Ru and poly-Si electrode were studied. With 750°C annealing after Ta2O5 deposition, a 12-nm-thick Ta2O5 on Pt and Ru shows a SiO2 equivalent thickness (t eq) of 0.9 nm. We found that Ta2O5 on Pt and Ru shows (110) and (001) orientation, respectively. There is no interaction between Ta2O5 and these electrodes with 750°C annealing. t eq on Pt and Ru decreases with annealing temperature increase. On the other hand, Ta2O5 on poly-Si is randomly oriented and its t eq does not change with annealing temperature increase. The relative dielectric constant of Ta2O5 on Pt and Ru, which is highly oriented with 750°C annealing, is estimated over 50. It is clear that the Ta2O5 electrical properties are strongly related with its crystallinity.

Liquid delivery MOCVD of Ruthenium Films from Ru(EtCp)2 with Toluene Solvent

“…The diffraction peaks at 2θ 38.39°, 42.15°, 44°, and 58.32° correspond to the (100), (002), (101), and (102) planes of Ru, respectively. The degree of preferred orientation is estimated from the X-ray peak intensity ratio of (002) and (101) The existing of a preferred (002) orientation for deposited ruthenium films reveals their suitability for bottom electrodes of DRAMs with BST and Ta 2 O 5 as capacitor dielectrics (19,20,21). …”

Ruthenium Films Deposited by Liquid‐Delivery MOCVD Using Bis(ethylcyclopentadienyl)ruthenium with Toluene as the Solvent

“…The existence of a preferred (002) orientation for deposited ruthenium films evidences their suitability for bottom electrodes of dynamic random-access memories (DRAMs) with barium strontium titanates (BSTs) and Ta 2 O 5 as the capacitor dielectrics. [21][22][23] The formation of a crystalline RuO 2 phase could not be observed at all deposition temperatures. Furthermore, field-emission scanning electron microscopy (FESEM) investigations of the Ru film microstructure and surface morphology are shown in Figures 5 and 6 …”

Material and electrical characterizations of high-k Ta2O5 dielectric material deposited on polycrystalline silicon and single crystalline substrate

“…In contrast to previous literature, this research studies the influence of substrate on dielectric performance [5][6][7]. Ta 2 O 5 dielectrics were sputtered on top of a polysilicon substrate in one group of samples, and on top of single crystalline substrate in another [8][9][10]. Ta 2 O 5 dielectric-based electronic devices have been on the market.…”