ALD of Hafnium Dioxide Thin Films Using the New Alkoxide Precursor Hafnium 3-Methyl-3-pentoxide, Hf(mp)4

Abstract

A new alkoxide precursor, Hf(mp) 4 [mp = 3-methyl-3-pentoxide, OC(CH 3 )(C 2 H 5 ) 2 ] has been employed in the atomic layer deposition (ALD) of HfO 2 thin films using water (H 2 O) as the oxygen source. The self-limiting ALD process via alternate surface reactions of Hf(mp) 4 and H 2 O is confirmed from thickness measurements of the HfO 2 films grown with varied Hf(mp) 4 supply time and number of Hf(mp) 4 /H 2 O ALD cycles. The ALD temperature window for this precursor is found to be between 250 and 350°C. Under optimal reaction conditions, the growth rate of the HfO 2 films is ∼0.9 Å per cycle. Amorphous films can be obtained across the entire temperature range with atomically flat and uniform surfaces. X-ray photoelectron spectroscopy (XPS) and depth-profiling Auger electron spectroscopy (AES) indicate that the films are stoichiometric with negligible amounts (less than 2 %) of carbon impurities.

Atomic Layer Deposition of Groups 4 and 5 Transition Metal Oxide Thin Films: Focus on Heteroleptic Precursors

“…For example, a carbon content as high as 8 at.‐% was reported in the case of the Hf(O t Bu) 4 /O 3 process, 4 − 5 at.‐% of carbon and as much as 14 − 18 at.‐% of hydrogen as impurities when using Hf(mp) 4 and water . With the notable exception of Ti(OMe) 4 , which exists as a tetramer under standard conditions, and presented self‐limiting GPC at 350°C when used together with water, alkoxides generally exhibit poor thermal stability, and the self‐limiting growth has been limited to well below 300°C (Table ) …”

Synthesis and Characterization of Nickel(II) Aminoalkoxides: Application to Molecular Precursors for MOCVD of Ni Thin Films

“…[39][40][41] Our research has been focused on the development of novel precursors for MOCVD and ALD and preparation of metal and metal oxide thin films using these precursors by MOCVD and ALD techniques. [42][43][44][45][46][47][48] In this work, we synthesized novel Ni II aminoalkoxide complexes using various dialkylamino alcohols ligands, namely, 1-(dimethylamino)-2-methyl-2-propanol (dmampH), 1-(diethylamino)-2-methyl-2-propanol (deampH), and 1-(ethylmethylamino)-2-methyl-2-propanol (emampH), and characterized each by spectroscopic methods and X-ray single crystallography. From our preliminary CVD studies, the nickel aminoalkoxide complexes were appropriate as precursors for the deposition of nickel films without external reducing agents such as hydrogen.…”

The Atomic Layer Deposition of HfO2 and ZrO2 using Advanced Metallocene Precursors and H2O as the Oxygen Source

“…Although some precursors offer such conditions to varying extents, improvement in one or more of these areas for the growth of HfO 2 and ZrO 2 would be a notable advance. To date, a variety of ligand types have been used for the ALD of HfO 2 and ZrO 2 , including some traditional examples such as halides, [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] alkylamides, [20][21][22][23][24][25][26][27][28] and alkoxides, [29][30][31][32][33][34][35][36][37][38][39][40] as well as others. [41][42][43] Recent studies, however, have demonstrated the ALD growth of these materials using hafnocene-and zirconocene-based precursors, and the potential viability of the resulting films in device applications.…”