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Wostatek T, Chirala VYMR, Stoddard N, Civas EN, Pimputkar S, Schimmel S. Ammonothermal Crystal Growth of Functional Nitrides for Semiconductor Devices: Status and Potential. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3104. [PMID: 38998188 PMCID: PMC11242142 DOI: 10.3390/ma17133104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/07/2024] [Accepted: 06/10/2024] [Indexed: 07/14/2024]
Abstract
The state-of-the-art ammonothermal method for the growth of nitrides is reviewed here, with an emphasis on binary and ternary nitrides beyond GaN. A wide range of relevant aspects are covered, from fundamental autoclave technology, to reactivity and solubility of elements, to synthesized crystalline nitride materials and their properties. Initially, the potential of emerging and novel nitrides is discussed, motivating their synthesis in single crystal form. This is followed by a summary of our current understanding of the reactivity/solubility of species and the state-of-the-art single crystal synthesis for GaN, AlN, AlGaN, BN, InN, and, more generally, ternary and higher order nitrides. Investigation of the synthesized materials is presented, with a focus on point defects (impurities, native defects including hydrogenated vacancies) based on GaN and potential pathways for their mitigation or circumvention for achieving a wide range of controllable functional and structural material properties. Lastly, recent developments in autoclave technology are reviewed, based on GaN, with a focus on advances in development of in situ technologies, including in situ temperature measurements, optical absorption via UV/Vis spectroscopy, imaging of the solution and crystals via optical (visible, X-ray), along with use of X-ray computed tomography and diffraction. While time intensive to develop, these technologies are now capable of offering unprecedented insight into the autoclave and, hence, facilitating the rapid exploration of novel nitride synthesis using the ammonothermal method.
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Affiliation(s)
- Thomas Wostatek
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Chair of Electron Devices (LEB), Cauerstraße 6, 91058 Erlangen, Germany
| | - V. Y. M. Rajesh Chirala
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Chair of Electron Devices (LEB), Cauerstraße 6, 91058 Erlangen, Germany
| | - Nathan Stoddard
- Department of Materials Science and Engineering, Lehigh University, 5 E Packer Avenue, Bethlehem, PA 18015, USA
| | - Ege N. Civas
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Chair of Electron Devices (LEB), Cauerstraße 6, 91058 Erlangen, Germany
| | - Siddha Pimputkar
- Department of Materials Science and Engineering, Lehigh University, 5 E Packer Avenue, Bethlehem, PA 18015, USA
| | - Saskia Schimmel
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Chair of Electron Devices (LEB), Cauerstraße 6, 91058 Erlangen, Germany
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Schimmel S, Salamon M, Tomida D, Neumeier S, Ishiguro T, Honda Y, Chichibu SF, Amano H. High-Energy Computed Tomography as a Prospective Tool for In Situ Monitoring of Mass Transfer Processes inside High-Pressure Reactors-A Case Study on Ammonothermal Bulk Crystal Growth of Nitrides including GaN. MATERIALS (BASEL, SWITZERLAND) 2022; 15:6165. [PMID: 36079544 PMCID: PMC9457664 DOI: 10.3390/ma15176165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 08/29/2022] [Accepted: 08/31/2022] [Indexed: 06/15/2023]
Abstract
For the fundamental understanding and the technological development of the ammonothermal method for the synthesis and crystal growth of nitrides, an in situ monitoring technique for tracking mass transport of the nitride throughout the entire autoclave volume is desirable. The feasibility of using high-energy computed tomography for this purpose was therefore evaluated using ex situ measurements. Acceleration voltages of 600 kV were estimated to yield suitable transparency in a lab-scale ammonothermal setup for GaN crystal growth designed for up to 300 MPa operating pressure. The total scan duration was estimated to be in the order of 20 to 40 min, which was sufficient given the comparatively slow crystal growth speed in ammonothermal growth. Even shorter scan durations or, alternatively, lower acceleration voltages for improved contrast or reduced X-ray shielding requirements, were estimated to be feasible in the case of ammonoacidic growth, as the lower pressure requirements for this process variant allow for thinned autoclave walls in an adapted setup designed for improved X-ray transparency. Promising nickel-base and cobalt-base alloys for applications in ammonothermal reactors with reduced X-ray absorption in relation to the maximum operating pressure were identified. The applicability for the validation of numerical simulations of the growth process of GaN, in addition to the applicability of the technique to further nitride materials, as well as larger reactors and bulk crystals, were evaluated.
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Affiliation(s)
- Saskia Schimmel
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Crystal Growth Lab, Materials for Electronics and Energy Technology (i-MEET), Martensstraße 7, 91058 Erlangen, Germany
| | - Michael Salamon
- Fraunhofer IIS, Fraunhofer Institute for Integrated Circuits IIS, Division Development Center X-ray Technology, 90768 Fürth, Germany
| | - Daisuke Tomida
- Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8601, Japan
| | - Steffen Neumeier
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute I: General Materials Properties, Martensstraße 5, 91058 Erlangen, Germany
| | - Tohru Ishiguro
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Yoshio Honda
- Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8601, Japan
| | - Shigefusa F. Chichibu
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Hiroshi Amano
- Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8601, Japan
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Kim K, Kang DW, Yun CY, Choi Y, Lee JW. Fundamental reaction kinetics of high-pressure reductive amination of polyalkylene glycol. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2021.11.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Numerical Simulation of Ammonothermal Crystal Growth of GaN—Current State, Challenges, and Prospects. CRYSTALS 2021. [DOI: 10.3390/cryst11040356] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Numerical simulations are a valuable tool for the design and optimization of crystal growth processes because experimental investigations are expensive and access to internal parameters is limited. These technical limitations are particularly large for ammonothermal growth of bulk GaN, an important semiconductor material. This review presents an overview of the literature on simulations targeting ammonothermal growth of GaN. Approaches for validation are also reviewed, and an overview of available methods and data is given. Fluid flow is likely in the transitional range between laminar and turbulent; however, the time-averaged flow patterns likely tend to be stable. Thermal boundary conditions both in experimental and numerical research deserve more detailed evaluation, especially when designing numerical or physical models of the ammonothermal growth system. A key source of uncertainty for calculations is fluid properties under the specific conditions. This originates from their importance not only in numerical simulations but also in designing similar physical model systems and in guiding the selection of the flow model. Due to the various sources of uncertainty, a closer integration of numerical modeling, physical modeling, and the use of measurements under ammonothermal process conditions appear to be necessary for developing numerical models of defined accuracy.
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Becker P, Wonglakhon T, Zahn D, Gudat D, Niewa R. Approaching Dissolved Species in Ammonoacidic GaN Crystal Growth: A Combined Solution NMR and Computational Study. Chemistry 2020; 26:7008-7017. [PMID: 32011786 PMCID: PMC7317737 DOI: 10.1002/chem.201904657] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/29/2020] [Indexed: 11/11/2022]
Abstract
Solutions of gallium trihalides GaX3 (X=F, Cl, Br, I) and their ammoniates in liquid ammonia were studied at ambient temperature under autogenous pressure by multinuclear (71 Ga, 35 Cl, 81 Br) NMR spectroscopy. To unravel the role of pH, the analyses were done both in absence and in presence of ammonium halides, which are employed as mineralizers during ammonoacidic gallium nitride crystal growth. While gallium trifluoride and its ammoniate were found to be too sparingly soluble to give rise to a NMR signal, the spectra of solutions of the heavier halides reveal the presence of a single gallium-containing species in all cases. DFT calculations and molecular dynamics simulations suggest the identification of this species as consisting of a [Ga(NH3 )6 ]3+ cation and up to six surrounding halide anions, resulting in an overall trend towards negative complex charge. Quantitative 71 Ga NMR studies on saturated solutions of GaCl3 containing various amounts of additional NH4 Cl revealed a near linear increase of GaCl3 solubility with mineralizer concentration of about 0.023 mol GaCl3 per mol NH4 Cl at room temperature. These findings reflect the importance of Coulombic shielding for the inhibition of oligomerization and precipitation processes and help to rationalize both the low solubility of gallium halides in neutral ammonia solution and, in turn, the proliferating effect of the mineralizer during ammonoacidic gallium nitride formation.
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Affiliation(s)
- Peter Becker
- Institute of Inorganic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Tanakorn Wonglakhon
- Department of Chemistry and Pharmacy, Friedrich Alexander University Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Dirk Zahn
- Department of Chemistry and Pharmacy, Friedrich Alexander University Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Dietrich Gudat
- Institute of Inorganic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Rainer Niewa
- Institute of Inorganic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
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Cordes N, Bräuniger T, Schnick W. Ammonothermal Synthesis of EAM
O2
N (EA
= Sr, Ba; M
= Nb, Ta) Perovskites and 14
N Solid-State NMR Spectroscopic Investigations of AM
(O,N)3
(A
= Ca, Sr, Ba, La). Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800827] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Niklas Cordes
- Department of Chemistry; University of Munich (LMU); Butenandtstrasse 5-13 81388 Munich Germany
| | - Thomas Bräuniger
- Department of Chemistry; University of Munich (LMU); Butenandtstrasse 5-13 81388 Munich Germany
| | - Wolfgang Schnick
- Department of Chemistry; University of Munich (LMU); Butenandtstrasse 5-13 81388 Munich Germany
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In situ investigation of decomposing ammonia and ammonobasic solutions under supercritical conditions via UV/vis and Raman Spectroscopy. J Supercrit Fluids 2018. [DOI: 10.1016/j.supflu.2017.12.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Häusler J, Niklaus R, Minár J, Schnick W. Ammonothermal Synthesis and Optical Properties of Ternary Nitride Semiconductors Mg-IV-N 2 , Mn-IV-N 2 and Li-IV 2 -N 3 (IV=Si, Ge). Chemistry 2017; 24:1686-1693. [PMID: 29205562 DOI: 10.1002/chem.201704973] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Indexed: 11/09/2022]
Abstract
Grimm-Sommerfeld analogous nitrides MgSiN2 , MgGeN2 , MnSiN2 , MnGeN2 , LiSi2 N3 and LiGe2 N3 (generally classified as II-IV-N2 and I-IV2 -N3 ) are promising semiconductor materials with great potential for application in (opto)electronics or photovoltaics. A new synthetic approach for these nitride materials was developed using supercritical ammonia as both solvent and nitride-forming agent. Syntheses were conducted in custom-built high-pressure autoclaves with alkali metal amides LiNH2 , NaNH2 or KNH2 as ammonobasic mineralizers, which accomplish an adequate solubility of the starting materials and promote the formation of reactive intermediate species. The reactions were performed at temperatures between 870 and 1070 K and pressures up to 230 MPa. All studied compounds crystallize in wurtzite-derived superstructures with orthorhombic space groups Pna21 (II-IV-N2 ) and Cmc21 (I-IV2 -N3 ), respectively, which was confirmed by powder X-ray diffraction. Optical bandgaps were estimated from diffuse reflectance spectra using the Kubelka-Munk function (MgSiN2 : 4.8 eV, MgGeN2 : 3.2 eV, MnSiN2 : 3.5 eV, MnGeN2 : 2.5 eV, LiSi2 N3 : 4.4 eV, LiGe2 N3 : 3.9 eV). Complementary DFT calculations were carried out to gain insight into the electronic band structures of these materials and to corroborate the optical measurements.
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Affiliation(s)
- Jonas Häusler
- Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13 (D), 81377, Munich, Germany
| | - Robin Niklaus
- Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13 (D), 81377, Munich, Germany
| | - Ján Minár
- New Technologies Research Centre, University of West Bohemia, Univerzitni 8, 30614, Pilsen, Czech Republic
| | - Wolfgang Schnick
- Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13 (D), 81377, Munich, Germany
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Häusler J, Schimmel S, Wellmann P, Schnick W. Ammonothermal Synthesis of Earth-Abundant Nitride Semiconductors ZnSiN 2 and ZnGeN 2 and Dissolution Monitoring by In Situ X-ray Imaging. Chemistry 2017; 23:12275-12282. [PMID: 28426151 DOI: 10.1002/chem.201701081] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Indexed: 11/06/2022]
Abstract
In this contribution, first synthesis of semiconducting ZnSiN2 and ZnGeN2 from solution is reported with supercritical ammonia as solvent and KNH2 as ammonobasic mineralizer. The reactions were conducted in custom-built high-pressure autoclaves made of nickel-based superalloy. The nitrides were characterized by powder X-ray diffraction and their crystal structures were refined by the Rietveld method. ZnSiN2 (a=5.24637(4), b=6.28025(5), c=5.02228(4) Å, Z=4, Rwp =0.0556) and isotypic ZnGeN2 (a=5.46677(10), b=6.44640(12), c=5.19080(10) Å, Z=4, Rwp =0.0494) crystallize in the orthorhombic space group Pna21 (no. 33). The morphology and elemental composition of the nitrides were examined by electron microscopy and energy-dispersive X-ray spectroscopy (EDX). Well-defined single crystals with a diameter up to 7 μm were grown by ammonothermal synthesis at temperatures between 870 and 1070 K and pressures up to 230 MPa. Optical properties have been analyzed with diffuse reflectance measurements. The band gaps of ZnSiN2 and ZnGeN2 were determined to be 3.7 and 3.2 eV at room temperature, respectively. In situ X-ray measurements were performed to exemplarily investigate the crystallization mechanism of ZnGeN2 . Dissolution in ammonobasic supercritical ammonia between 570 and 670 K was observed which is quite promising for the crystal growth of ternary nitrides under ammonothermal conditions.
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Affiliation(s)
- Jonas Häusler
- Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13 (D), 81377, Munich, Germany
| | - Saskia Schimmel
- Materials Department 6, Friedrich-Alexander-University, Erlangen-Nürnberg (FAU), Martensstr. 7, 91058, Erlangen, Germany
| | - Peter Wellmann
- Materials Department 6, Friedrich-Alexander-University, Erlangen-Nürnberg (FAU), Martensstr. 7, 91058, Erlangen, Germany
| | - Wolfgang Schnick
- Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13 (D), 81377, Munich, Germany
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Pimputkar S, Malkowski TF, Griffiths S, Espenlaub A, Suihkonen S, Speck JS, Nakamura S. Stability of materials in supercritical ammonia solutions. J Supercrit Fluids 2016. [DOI: 10.1016/j.supflu.2015.10.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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