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8 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Layered synthetic microstructure technology considerations for the extreme ultraviolet

It is demonstrated that layered synthetic microstructures (LSMs) can provide mirrors with enhanced normal incidence reflectance in the 300-A spectral region. Experimental results are presented for Pt-Si and Ir-Si structures fabricated by electron-beam deposition at pressures of about 10 to the -6th Torr, and it is shown that the enhancement is realized over a limited bandwidth of 75 A. One potential application of LSMs is their use as coatings on diffraction gratings to enhance normal incidence reflection efficiencies. Preliminary results for the Ir-Si combination on a diffraction grating show that LSMs enhance grating efficiencies in the EUV by a factor of about 3.

Keski-Kuha, R. A. M.↗
DOE OSTI2020

Materials Data on SiIr by Materials Project

IrSi is Modderite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ir4+ is bonded to six equivalent Si4- atoms to form a mixture of distorted edge, corner, and face-sharing IrSi6 octahedra. The corner-sharing octahedra tilt angles range from 43–61°. There are a spread of Ir–Si bond distances ranging from 2.43–2.56 Å. Si4- is bonded in a 6-coordinate geometry to six equivalent Ir4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si4Ir3 by Materials Project

Ir3Si4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent Ir sites. In the first Ir site, Ir is bonded in a 7-coordinate geometry to seven Si atoms. There are a spread of Ir–Si bond distances ranging from 2.33–2.69 Å. In the second Ir site, Ir is bonded in a 6-coordinate geometry to six Si atoms. There are a spread of Ir–Si bond distances ranging from 2.35–2.51 Å. In the third Ir site, Ir is bonded in a 7-coordinate geometry to seven Si atoms. There are a spread of Ir–Si bond distances ranging from 2.42–2.70 Å. There are four inequivalent Si sites. In the first Si site, Si is bonded to four Ir atoms to form a mixture of distorted edge and corner-sharing SiIr4 tetrahedra. In the second Si site, Si is bonded in a 6-coordinate geometry to six Ir atoms. In the third Si site, Si is bonded in a 8-coordinate geometry to six Ir atoms. In the fourth Si site, Si is bonded in a 4-coordinate geometry to four Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SiIr3 by Materials Project

Ir3Si crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. there are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a distorted square co-planar geometry to four equivalent Si atoms. All Ir–Si bond lengths are 2.64 Å. In the second Ir site, Ir is bonded in a distorted water-like geometry to two equivalent Si atoms. Both Ir–Si bond lengths are 2.44 Å. Si is bonded in a 8-coordinate geometry to eight Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si3Ir by Materials Project

IrSi3 is Sodium arsenide structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ir4+ is bonded in a 5-coordinate geometry to eleven Si+1.33- atoms. There are a spread of Ir–Si bond distances ranging from 2.49–2.80 Å. There are two inequivalent Si+1.33- sites. In the first Si+1.33- site, Si+1.33- is bonded in a 1-coordinate geometry to four equivalent Ir4+ atoms. In the second Si+1.33- site, Si+1.33- is bonded in a trigonal planar geometry to three equivalent Ir4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si3Ir by Materials Project

IrSi3 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Ir4+ is bonded in a 9-coordinate geometry to nine equivalent Si+1.33- atoms. There are three shorter (2.51 Å) and six longer (2.64 Å) Ir–Si bond lengths. Si+1.33- is bonded in a 7-coordinate geometry to three equivalent Ir4+ and four equivalent Si+1.33- atoms. There are two shorter (2.38 Å) and two longer (2.40 Å) Si–Si bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si2Ir3 by Materials Project

Ir3Si2 crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 5-coordinate geometry to six equivalent Ir and five Si atoms. All Ir–Ir bond lengths are 2.75 Å. There are three shorter (2.33 Å) and two longer (2.72 Å) Ir–Si bond lengths. In the second Ir site, Ir is bonded in a 11-coordinate geometry to five Ir and six Si atoms. There are one shorter (2.54 Å) and one longer (2.91 Å) Ir–Ir bond lengths. There are three shorter (2.65 Å) and three longer (2.75 Å) Ir–Si bond lengths. There are two inequivalent Si sites. In the first Si site, Si is bonded in a 3-coordinate geometry to nine Ir atoms. In the second Si site, Si is bonded in a 8-coordinate geometry to eight Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SiIr2 by Materials Project

Ir2Si crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ir sites. In the first Ir site, Ir is bonded to six equivalent Ir and five equivalent Si atoms to form a mixture of distorted corner and face-sharing IrSi5Ir6 trigonal bipyramids. All Ir–Ir bond lengths are 2.79 Å. There are three shorter (2.42 Å) and two longer (2.75 Å) Ir–Si bond lengths. In the second Ir site, Ir is bonded in a 6-coordinate geometry to eight Ir and six equivalent Si atoms. Both Ir–Ir bond lengths are 2.75 Å. All Ir–Si bond lengths are 2.79 Å. Si is bonded in a 11-coordinate geometry to eleven Ir atoms.

36 MATERIALS SCIENCE↗