Atomic layer deposition (ALD) processes for HfO2 and HfxSi1−xO2 high-k dielectric thin films using liquid precursors and ozone were evaluated. Tetrakis(ethylmethylamino)hafnium (TEMAHf) precursor provides HfO2 films with superior quality as compared to Hf(t-butoxide)4 precursor in terms of deposition rate, purity, and electrical properties of the films. ALD processes for hafnium silicate films have been developed by co-injection of TEMAHf and tetrakis(ethylmethylamino) silicon precursors. Alternating pulses of the Hf/Si precursor vapor mixture and ozone allow process temperatures below 400 °C to grow HfxSi1−xO2 film. The Hf and Si precursors can be converted to vapor for delivery to the deposition chamber either by bubbling an inert carrier gas separately through each liquid or by using a liquid vaporization unit. The co-injection process enables the formation of homogeneous single-layer hafnium silicate films as deposited.

HfO 2 films have been grown with two atomic layer deposition (ALD) chemistries: (a) tetrakis(ethylmethylamino)hafnium (TEMAHf)+O3 and (b) HfCl4+H2O. The resulting films were studied as a function of ALD cycle number on Si(100) surfaces prepared with chemical oxide, HF last, and NH3 annealing. TEMAHf+O3 growth is independent of surface preparation, while HfCl4+H2O shows a surface dependence. Rutherford backscattering shows that HfCl4+H2O coverage per cycle is l3% of a monolayer on chemical oxide while TEMAHf+O3 coverage per cycle is 23% of a monolayer independent of surface. Low energy ion scattering, x-ray reflectivity, and x-ray photoelectron spectroscopy were used to understand film continuity, density, and chemical bonding. TEMAHf+O3 ALD shows continuous films, density >9g∕cm3, and bulk Hf–O bonding after 15 cycles [physical thickness (Tphys)=1.2±0.2nm] even on H-terminated Si(100). Conversely, on H-terminated Si(100), HfCl4+H2O requires 50 cycles (Tphys∼3nm) for continuous films and bulk Hf–O bonding. TEMAHf+O3 ALD was implemented in HfO2∕TiN transistor gate stacks, over the range 1.2nm⩽Tphys⩽3.3nm. Electrical results are consistent with material analysis suggesting that at Tphys=1.2nm HfO2 properties begin to deviate from thick film properties. At Tphys=1.2nm, electrical thickness scaling slows, gate current density begins to deviate from scaling trendlines, and no hard dielectric breakdown occurs. Most importantly, n-channel transistors show improvement in peak and high field electron mobility as Tphys scales from 3.3 to 1.2nm. This improvement may be attributed to reduced charge trapping and Coulomb scattering in thinner films. Scaled HfO2 enables 1nm equivalent oxide thickness and 82% of universal SiO2 mobility.

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We describe pyrolytic laser assisted chemical vapor deposition of Al from dimethylethylamine-alane with 514-nm radiation from an Ar ion laser. High purity Al lines with resistivity close to bulk Al are reported for a range of operating conditions. The relationship between operating parameters and materials properties of the deposited lines is delineated. Results from deposition on different substrates, Pt, Au, W, and Si, provide insight into thermal and nucleation effects in the laser writing process. Based on the observed nucleation behavior, we demonstrate a two-step fast writing process involving fast laser nucleation of lines, followed by selective chemical vapor deposition of Al on the nucleated pattern.

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