Functional ultrawide bandgap gallium oxide and zinc gallate thin films and novel deposition technologies (2021.-2023.)

Type: European Regional Development Fund

Agreement No: 1.1.1.1/20/A/057

Duration: 01.01.2021 - 30.06.2023.

Project Leader: Institute of Solid State Physics University of Latvia (ISSP UL), Dr.hab.phys. Juris Purans

Project partners: SIA AGL Technologies, Dr.pys. Andis Azens, SIA BC Corporation Limited Dr.phys. Lauris Dimitrocenko.

Total budget: 537 004 EUR

ISSP UL budget: 322 000 EUR

Project description:

Gallium oxide Ga2O3 has become one of the most investigated materials of today. Nearly every issue of material-related scientific journals contains articles on growth, material properties, or device applications of gallium oxide. The reason for this large interest is the extremely promising properties for electronic and optical applications of this wide bandgap material, together with the relatively un-expensive substrate wafers. Very recently, ultrawide-bandgap spinel zinc gallate ZnGa2O4 has been demonstrated to exhibit several benefits over gallium oxide that merits to be investigated more deeply.

The aim of this industrial research project is to develop advanced high rate PVD magnetron sputtering and MOCVD technologies for deposition of functional ultrawide-bandgap gallium oxide Ga2O3 and zinc gallate ZnGa2O4 thin films for optoelectronics and electronics applications.

The main goals are:

  • To develop high rate PVD magnetron sputtering technology for deposition of pure and doped (p-type dopants and RE) amorphous and crystalline gallium oxide Ga2O3 thin films and ZnGa2O4 thin films. The applications in focus are (1) deep UV TCOs/TSOs and (2) efficient inorganic luminescence devices (a-Ga2Ox:RE).
  • To develop MOCVD technology of Ga2O3 and ZnGa2O4 thin films deposition and to establish epitaxial n- and p-type Ga2O3 and ZnGa2O4 thin film growth processes for deep UV optoelectronics and electronics applications.

The proposed Industrial research project will be implemented by ISSP LU, SIA AGL Technologies and SIA BC Corporation Limited. This Interdisciplinary Project consists of the research activities in Physical and Chemical sciences (1.3, 1.4) and Materials engineering (2.5).

 
 

ON THE IMPLEMENTATION OF THE PROJECT (PERIOD 01.04.2021.-30.06.2021.)

23.07.2021.

Preparation of the sputtering system for use in two-magnetron DC, RF and HiPIMS sputtering configuration was continued. The design and installation of target containers for metallic Ga targets suitable for reactive sputtering from a liquid metal target and arrangement of the chamber interior geometry for sputtering in upward direction was completed. Testing of the installed target has been started. Practical knowledge related to the growth of Ga2O3 and ZnGa2O4 thin films on their structure, electrical and optical physical properties has been acquired. As a result of the research, a scientific article “A comprehensive study of the structure and properties of nanocrystalline zinc peroxide” was prepared and submitted (activity 1).

Plasma Optical Emission spectroscopy line has been installed and tuned, Gallium spectral lines have been identified for process control (activity 1).

Aixtron (AIX-200RF) MOCVD system preparation for Ga2O3 and ZnGa2O4 thin film deposition has been performed: fabrication and testing of a new silicon carbide heating element in an oxidative atmosphere; growing Ga2O3 and ZnGa2O4  thin films with MOCVD on sapphire substrates of different orientations; engineering and drawing of a new reactor design in collaboration with SIA BC Corporation Limited (activity 2).

Ab-initio calculations of doped Ga2O3 was conducted. Analysis of material atoms, electronic and oscillation properties, analysis of formation energies of various configurations were performed. The article “Ab-initio calculations of oxygen vacancy in Ga2O3 crystals” was published in an internationally cited journal: LATVIAN JOURNAL OF PHYSICS AND TECHNICAL SCIENCES, Vol. 58, N 2 (2021), 3-11 (activity 3).

An open procurement was announced for the purchase of substrates, chemicals and other laboratory equipment necessary for the implementation of the project. Preparation and testing of structural and morphology characterization methods (XRD, XPS, SEM, TEM) for Ga2O3 and ZnGa2O4 thin films has been continued (activity 4).

 

ON THE IMPLEMENTATION OF THE PROJECT (PERIOD 01.01.2021. - 31.03.2021.)

02.04.2021.

As part of Project No 1.1.1.1/20/A/057 preparation and testing of the vacuum system, gas inlet system, substrate heating system, target cooling and heating system and connection of the necessary (DC, RF, HiPIMS) power supplies for use in two-magnetron sputtering configuration has been started. Development of design of target containers for metallic Ga targets suitable for reactive sputtering from a liquid metal target and arrangement of the chamber interior geometry for sputtering in upward direction also is started (activity 1).

Magnetron sputtering targets purchase order placed (activity 1).

Aixtron (AIX-200RF) MOCVD system preparation for Ga2O3 and ZnGa2O4 thin film deposition has been done: testing of reactor stability at high temperature while using oxidative precursor; engineering and drawing of a new reactor design in collaboration with SIA BC Corporation Limited; replacement of malfunctioning parts (activity 2).

Study was conducted and the formation energy and transition levels of oxygen vacan­cies in β-Ga2O3 crystal using the B3LYP hybrid exchange-correlation functional within the LCAO-DFT approach was calculated. As result information for article “Ab-initio calculations of oxygen vacancy in Ga2O3 crystals” was prepared (activity 3).

Preparation and testing of structural and morphology characterization methods (XRD, XPS, SEM, TEM) for Ga2O3 and ZnGa2O4 thin films has been done (activity 4).