High quality HZO and AlN films grown by industrially compatible techniques for next generation electronic and sensing devices


Project Director: Dr. Besleaga Stan Cristina

Project ID: PN-III-P1-1.1-TE-2019-0688

Project Director: Dr. Cristina Besleaga Stan

Project Type: National

Project Program:  HUMAN RESOURCES, TE

Funded by: Romanian National Authority for Scientific Research, UEFISCDI

Contractor: National Institute of Materials Physics

Project Status: In progress

Start Date: 13 September, 2020

End Date: 14 September, 2022

The project activities are designed to find the answers to several critical pending issues, such as the pyroelectricity and the origin of ferroelectricity in HZO and of the negative capacitance effect, or the sustainability and limits of AlN-based sensors in harsh environments. Ferroelectric memories, metal-insulator-semiconductor and thin film field effect transistors structures will be fabricated and subsequently analyzed, and the results will be interpolated and discussed with
respect to the physico-chemical features of the AlN and HZO thin films. CVD and ALD techniques are underdeveloped in Romania, even though they have demonstrated tremendous advantages and applicability potential for the development and large-scale production of nano- and micro-electronics. Thereby, the development and successful application of the CVD and ALD techniques, in the framework of this project, for the deposition of high-quality thin films, will represent an important achievement, of high-interest, at both regional and national level.

  • Cristina Besleaga
  • Andrei Nitescu
  • Liliana Marinela Balescu
  • George Stan
  • Andra Georgia Boni
  • Mihaela Botea
  • Andrei Tomulescu
  • Andrei Cristian Kuncser
  • Florentina Neatu
  • In stage I, the first preliminary tests were performed to obtain thin layers of HfO2 by the ALD method.

 

  • In stage II of the project, the procedures for obtaining HZO and AlN thin films through ALD and CVD were developed.
    The successful use of ALD and CVD techniques for the deposition of these materials represents an important evolution in the field of materials science, at regional and national level. These techniques are underdeveloped in Romania, even though they have demonstrated the extraordinary advantages of development and applicability for large-scale production in the USA and Western Europe.

Thin films were obtained by ALD or CVD using AnnealSys MC-050 equipment:

HfO2 films crystallized predominantly in the monoclinic phase, but the presence of the orthorhombic crystalline phase was was highlighted by XRD and SAED analyzes. The obtained films are pyroelectric. Moreover, the Capacitance-Voltage measurements indicated that they have semiconductor and ferroelectric properties.

The AlN films, deposited by CVD, have a hexagonal polycrystalline structure. They have a dielectric constant of ~ 12 and a breakthrough field greater than 12 MV/cm. The thin layers of AlN have been successfully integrated into pyrotechnic sensors that have been tested at various operating temperatures.

For HZO films, Tetrakis(ethylmethylamido)hafnium(IV) si Tetrakis(ethylmethylamido)zirconium (IV) liquid precursors were used.

For AlN films, Tris(dimethylamido)aluminum(III) and NH3 precursors were used.

The obtained films were investigated using the following equipment (methods): Rigaku SmartLab X-ray (XRD), JEM-ARM200F (JEOL) –HRTEM (TEM si SAED), J.A. Woollam Ellipsometer (optic), Keithley 4200 Semiconductor Analyzer, HP 4194A Impedance Analyzer (electrice), Jasco 6800-FV-BB (FTIR), Horiba LabRAM HR Evolution (Raman), NT-MDT SPM (AFM).

For stage II, the specific Objectives were:

O1. Obtaining HZO thin films by ALD method and the investigation of their physical properties; degree of completion: 100 %.

• HZO films were obtained by the ALD method. The impact of the variation of all process parameters on the structural, morphological, optical and electrical characteristics was tested.
• The obtained layers were integrated in capacitor / MIS type structures.
• The pyroelectric and ferroelectric character of HfO2 films was highlighted.

O2. Obtaining AlN thin films by CVD method and the investigation of their physical properties; degree of completion: 100 %.

• AlN films were obtained by the CVD method. The obtained layers were characterized structurally, morphologically, optically and electrically.
• The manufactured films were integrated in pyroelectric sensors that were tested at different temperatures.

O3. Dissemination: minimum one presentations at international conferences; degree of completion: 100 %.

The paper entitled “HfO2 / AlN multilayer devices and their functional characterization” was presented online, authors: Andrei Nitescu, Cristina Besleaga, Georgia Andra Boni, Lucian Pintilie, at the ICPAM-13 International Conference, an event that took place in Sant Feliu de Guixols, Spain, 24 - 30 September.


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