Deposition, Annealing, and Characterization of Tantalum Pentoxide Films

Abstract

Films of tantalum pentoxide (Ta2O5) have been fabricated by use of different precursor materials, deposition techniques and annealing procedures. Several analytical methods were appliedto study the layers. Fundamental properties and new data are reportedand related to practical features that are of importance in device design and manufacturing of advanced, highly integrated devices. This overview may facilitate the choice of an optimal combination of precursor, deposition technique and corresponding annealing procedure for aspecific application of these films in microelectronics, since the electrical properties reveal the potential of Ta2O5 films for the use in 64Mbit and 256Mbit DRAM devices as high dielectric constant material.

The Unusual Thermal Stabilization of MOCVD Precursors by the Dibenzoyl Methanate Group: Liquid Injection MOCVD of Tantalum Oxide and Niobium Oxide Using M(OEt)4(dbm) Precursors

“…[25] The major distortion from ideal octahedral geometry occurs along the O(4)±Nb(1)±O(1) axis (163.86(12)), and the cis O±Nb±O bond angles also show a significant deviation from the ideal 90, varying in the range 80.08(10)± 100.38 (12). The bite angle of the dbm ligand in 2 is 80.08(10), very close to the dbm bite angles of 80.5 (2) and 79.9(3) in 1, and the b-diketonate bite angles in Ta-(OMe) 4 (acac) [22] and Ta(OMe) 4 (thd) [22] of 78.9(5) and 79.3(2), respectively.…”

“…Both tantalum atoms, Ta(1) and Ta (2), exist in six-coordinate distorted octahedral environments. Crystal and data collection parameters are given in Table 1, and selected bond lengths and angles are summarized in Table 2.…”

“…Ta 2 O 5 has been used in dielectric capacitor layers in computer memories (DRAMs), [1,2] optical waveguides, [3] and corrosion resistant coatings. [4] Tantalum(V) oxide is also a component of several complex ferroelectric materials such as strontium bismuth tantalate, SrBi 2 Ta 2 O 9 , which has a potential application in non-volatile computer memories, [5,6] and lead scandium tantalate, Pb(Sc 0.5 Ta 0.5 )O 3 , which can be used in high-performance infrared imaging.…”

“…[7] Niobium oxide has applications in SrBi 2 Nb 2 O 9 non-volatile ferroelectric memory layers, [8] and in the Pb(Mg 0.33 Nb 0.66 )O 3 films used in transducers and electroceramic capacitors. [9] A variety of techniques, including reactive sputtering, [10] sol±gel deposition, [11] and MOCVD, [1,2,12,13] have been used for the deposition of Ta 2 O 5 and Nb 2 O 5 thin films. Of these techniques, MOCVD offers the most flexible approach, having the advantages of large area deposition capability, good composition and thickness control, and excellent conformal step coverage on complex structures.…”

Processing and Characterization of Ta2O5 Films Deposited by Pulsed Laser Ablation

“…It should be pointed out, however, that the presence of significant carbon contamination from the organic-metallic precursors may be a dominant factor that is causing the leakage current from the films. [16] Recently, the PLD technique has become widely recognized as a promising versatile technique for the fabrication of metal oxide thin films. [17] The major advantages of this technique over other deposition methods are the following: 1) the ability to transfer the original stoichiometry of a bulk target to the deposited film; 2) a high instantaneous rate of deposition; 3) the tight control over the thickness of the deposited film; 4) the capability to achieve reactive deposition in ambient reactive gas; and 5) a relatively simple deposition apparatus and easy to design automated systems capable of fabricating thin films with high reproducibility.…”