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Title: Tin Nitride Atomic Layer Deposition Using N2H4

Abstract

There is substantial lag in the development of atomic layer deposition (ALD) processes for nitrides compared to the high-quality, conformal oxides for which ALD has become the standard. A major factor in this disparity is the ready availability of highly reactive oxygen sources (mainly H2O, O2, and H2O2). High-energy nitrogen precursors are similarly required for the efficient incorporation of nitrogen in a film. Ammonia has often been used in conjunction with metal chlorides but requires relatively high temperatures for thermal ALD. Plasma-enhanced ALD can utilize molecular nitrogen as a precursor but can reduce film conformality on complex supports and damage the underlying substrate. Hydrazine (N2H4) is an alternative precursor which has been rarely explored for the fabrication of nitrides in ALD, but which is experiencing a surge in popularity due to its high reactivity, which enables the deposition of nitrides as-yet undemonstrated by ALD.(1) The added reactivity and volatility of liquid hydrazine may enable new reaction mechanisms, lower deposition temperatures, and conformality for high aspect ratio applications. Sn3N4 is a metastable semiconductor which shares a crystal structure with its analog, Si3N4; unlike Si3N4, Sn3N4 has only recently been grown by ALD,(2) being synthesized much more often through reactive sputtering.(3) Asmore » a binary, Sn3N4 has applications as a battery anode material, for photoelectrochemistry, and optoelectronic devices. We will report progress on the deposition of SnxNy films from tetrakis(dimethylamido) tin (TDMASn) and N2H4. Growth per cycle of this material (determined by x-ray reflectivity) is 0.4 A at 200 C, similar to the sole report of Sn3N4 from PE-ALD,(2) despite films being substantially Sn-rich. Identification of ALD growth window and self-limiting deposition characteristics are underway; initial testing indicates a competing chemical vapor deposition process which can be eliminated with adequate tuning of pulse/purge characteristics. A comparison of film conductivity and optical absorption at different growth temperatures will be presented. General issues of N2H4 purity and routes to prevent or control oxynitride formation will be discussed. (1) Du, L., et al. The First Atomic Layer Deposition Process for FexN Films. Chem. Comm., 2019, ASAP. DOI: 10.1039/C8CC10175B. (2) Stewart, D. M., et al. Tin Oxynitride Anodes by Atomic Layer Deposition for Solid-State Batteries. Chem. Mater. 2018, 30, 2526-34. (3) Caskey, C. M., et al. Semiconducting Properties of Spinel Tin Nitride and Other IV3N4 Polymorphs. J. Mater. Chem. C 2015, 3, 1389-96.« less

Authors:
 [1];  [1];  [1];  [1];  [1]
  1. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE National Renewable Energy Laboratory (NREL), Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1547255
Report Number(s):
NREL/PO-5K00-74285
DOE Contract Number:  
AC36-08GO28308
Resource Type:
Conference
Resource Relation:
Conference: Presented at the AVS 19th International Conference on Atomic Layer Deposition (ALD 2019), 21-24 July 2019, Bellevue, Washington
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; atomic layer deposition; nitride; hydrazine; high reactivity; deposition temperatures; semiconductor; crystal structure

Citation Formats

Greenaway, Ann, Shulda, Sarah, Link, Elisa M, Tamboli, Adele C, and Christensen, Steven T. Tin Nitride Atomic Layer Deposition Using N2H4. United States: N. p., 2019. Web.
Greenaway, Ann, Shulda, Sarah, Link, Elisa M, Tamboli, Adele C, & Christensen, Steven T. Tin Nitride Atomic Layer Deposition Using N2H4. United States.
Greenaway, Ann, Shulda, Sarah, Link, Elisa M, Tamboli, Adele C, and Christensen, Steven T. Wed . "Tin Nitride Atomic Layer Deposition Using N2H4". United States. https://www.osti.gov/servlets/purl/1547255.
@article{osti_1547255,
title = {Tin Nitride Atomic Layer Deposition Using N2H4},
author = {Greenaway, Ann and Shulda, Sarah and Link, Elisa M and Tamboli, Adele C and Christensen, Steven T},
abstractNote = {There is substantial lag in the development of atomic layer deposition (ALD) processes for nitrides compared to the high-quality, conformal oxides for which ALD has become the standard. A major factor in this disparity is the ready availability of highly reactive oxygen sources (mainly H2O, O2, and H2O2). High-energy nitrogen precursors are similarly required for the efficient incorporation of nitrogen in a film. Ammonia has often been used in conjunction with metal chlorides but requires relatively high temperatures for thermal ALD. Plasma-enhanced ALD can utilize molecular nitrogen as a precursor but can reduce film conformality on complex supports and damage the underlying substrate. Hydrazine (N2H4) is an alternative precursor which has been rarely explored for the fabrication of nitrides in ALD, but which is experiencing a surge in popularity due to its high reactivity, which enables the deposition of nitrides as-yet undemonstrated by ALD.(1) The added reactivity and volatility of liquid hydrazine may enable new reaction mechanisms, lower deposition temperatures, and conformality for high aspect ratio applications. Sn3N4 is a metastable semiconductor which shares a crystal structure with its analog, Si3N4; unlike Si3N4, Sn3N4 has only recently been grown by ALD,(2) being synthesized much more often through reactive sputtering.(3) As a binary, Sn3N4 has applications as a battery anode material, for photoelectrochemistry, and optoelectronic devices. We will report progress on the deposition of SnxNy films from tetrakis(dimethylamido) tin (TDMASn) and N2H4. Growth per cycle of this material (determined by x-ray reflectivity) is 0.4 A at 200 C, similar to the sole report of Sn3N4 from PE-ALD,(2) despite films being substantially Sn-rich. Identification of ALD growth window and self-limiting deposition characteristics are underway; initial testing indicates a competing chemical vapor deposition process which can be eliminated with adequate tuning of pulse/purge characteristics. A comparison of film conductivity and optical absorption at different growth temperatures will be presented. General issues of N2H4 purity and routes to prevent or control oxynitride formation will be discussed. (1) Du, L., et al. The First Atomic Layer Deposition Process for FexN Films. Chem. Comm., 2019, ASAP. DOI: 10.1039/C8CC10175B. (2) Stewart, D. M., et al. Tin Oxynitride Anodes by Atomic Layer Deposition for Solid-State Batteries. Chem. Mater. 2018, 30, 2526-34. (3) Caskey, C. M., et al. Semiconducting Properties of Spinel Tin Nitride and Other IV3N4 Polymorphs. J. Mater. Chem. C 2015, 3, 1389-96.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {7}
}

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