Comparison of Hafnium Dioxide and Zirconium Dioxide Grown by Plasma-Enhanced Atomic Layer Deposition for the Application of Electronic Materials

Sam Chance,Kim Kisslinger,Samuel Banks,Zhigang Xiao

doi:10.3390/cryst10020136

Sam Chance, Kim Kisslinger + Show 2 more

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https://doi.org/10.3390/cryst10020136

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Abstract

We report the growth of nanoscale hafnium dioxide (HfO2) and zirconium dioxide (ZrO2) thin films using remote plasma-enhanced atomic layer deposition (PE-ALD), and the fabrication of complementary metal-oxide semiconductor (CMOS) integrated circuits using the HfO2 and ZrO2 thin films as the gate oxide. Tetrakis (dimethylamino) hafnium (Hf[N(CH3)2]4) and tetrakis (dimethylamino) zirconium (IV) (Zr[N(CH3)2]4) were used as the precursors, while O2 gas was used as the reactive gas. The PE-ALD-grown HfO2 and ZrO2 thin films were analyzed using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). The XPS measurements show that the ZrO2 film has the atomic concentrations of 34% Zr, 2% C, and 64% O while the HfO2 film has the atomic concentrations of 29% Hf, 11% C, and 60% O. The HRTEM and XRD measurements show both HfO2 and ZrO2 films have polycrystalline structures. n-channel and p-channel metal-oxide semiconductor field-effect transistors (nFETs and pFETs), CMOS inverters, and CMOS ring oscillators were fabricated to test the quality of the HfO2 and ZrO2 thin films as the gate oxide. Current-voltage (IV) curves, transfer characteristics, and oscillation waveforms were measured from the fabricated transistors, inverters, and oscillators, respectively. The experimental results measured from the HfO2 and ZrO2 thin films were compared.

Highlights

This paper reports the results of remote plasma-enhanced atomic layer deposition (PE-ALD)
High-κ metal oxides such as hafnium dioxide (HfO2 ) and zirconium dioxide (ZrO2 ) thin films have been used as the gate oxide in the fabrication of metal-oxide-semiconductor field-effect transistors (MOSFETs) due to their high dielectric constant (κ) [1,2,3,4,5]
Lithography for the patterning in the device fabrication; (3) HF wet etching for etching silicon dioxide; (4) thermal diffusion for boron doping for the fabrication of the p-well and the source/drain of p-channel field-effect transistor (pFETs) and phosphorous doping for the making of the source/drain of n-channel field-effect transistors (nFETs); (5) plasma-enhanced atomic layer deposition of HfO2 and ZrO2 thin films for the gate oxide; and (6) electron beam evaporation of aluminum (Al)/chromium (Cr)/copper (Cu) thin films for the metal contact

Summary

Introduction

This paper reports the results of remote plasma-enhanced atomic layer deposition (PE-ALD). The objectives were to grow hafnium dioxide (HfO2 ) and zirconium dioxide (ZrO2 ) thin films at moderate substrate temperatures (200–400 ◦ C) for the application of high dielectric constant (κ) oxide, to compare the two PE-ALD-grown metal oxides, and to test their functionality and performance as the gate oxide in the fabrication of CMOS integrated circuits. The PE-ALD process is similar to the PE-CVD process, and has the advantage of the gas-phase plasma electron impact on the deposition to assist the dissociation of chemicals for active species; plasma-enhanced ALD can deposit films at much lower temperatures than thermal ALD [28,29]. The plasma-enhanced atomic layer deposition of HfO2 and ZrO2 thin films meets these requirements and could be used for the growth of a high dielectric constant (κ) gate oxide in the fabrication of integrated circuits (ICs)

Experimental Details

Results and Discussion

Summary

Summary fabricated withthe the HfO