Data Tables: Optical Thin-Film Materials

Tables showing parameters of the most frequently used physical vapor deposition materials for a wide variety of applications.

DATA TABLES: OPTICAL THIN-FILM MATERIALS

Identification

Physical Parameters

Material Name	Material Formula	Transparent Region(µm) (see note a)	Index at Wavelength (µm) (see note b)	Method/ Holder	Evap. Temp. °C) (see note c)
OXIDES
Aluminum Oxide	Al₂O₃	0.2 - 8	1.65, (0.50) 1.60, (1.00)	E-beam W	2100

Chromium Oxide	Cr₂O₃	0.6 - >5	2.20, (>0.8)	E-beam Mo	2000

Hafnium Dioxide	HfO₂	0.25 - 11	2.05, (0.30) 1.98, (0.40) 1.95, (0.50) 1.92, (0.7 - 1.5)	E-beam Mo	2500

Indium Oxide	In₂O₃	0.4 - 9	2.05, (0.50)	Resistance Alumina	600

Indium-Tin Oxide	ITO	0.4 - 2	2.05, (0.50) 1.45, (1.00)	Resistance Alumina	600

Niobium Pentoxide	Nb₂O₅	0.45 - >5	2.35, (0.45) 2.28, (0.50) 2.22, (0.60) 2.17, (1.00)	E-beam Ta	1400

Praseodymium Oxide	Pr₂O₃	0.3 - 8	1.84, (0.40) 1.78, (0.50) 1.75, (0.7 - 2)	E-beam Graphite	1900

Scandium Oxide	Sc₂O₃	0.3 - 12	1.92, (0.40) 1.89, (0.55) 1.86, (0.9 - 2)	E-beam Graphite	2400

Silicon Dioxide	SiO₂	0.2 - 7	1.52, (0.30) 1.49, (0.40) 1.46, (0.55) 1.44, (1.00)	E-beam Alumina, Graphite	1600

Silicon Monoxide	SiO	0.45 - 8	1.90, (0.50) 1.85, (1.00) 1.83, (4.00)	Resistance W, Ta, Mo	1100

Tantalum Pentoxide	Ta₂O₅	0.35 - 10	2.40, (0.30) 2.09, (0.55 - 2)	E-beam Ta, Graphite	2100

Tatanium Dioxide Ti₃O₅ starting material	TiO₂	0.45 - 11	2.45, (0.45) 2.36, (0.50) 2.29, (0.60) 2.25, (0.70) 2.21, (1.00)	E-beam Mo, Cu	1500

Yttrium Oxide	Y₂O₃	~0.25 - 11	1.83, (0.40) 1.80, (0.50) 1.75, (2.00) 1.42, (9.00)	E-beam W, Graphite	2400

Zirconium Oxide	ZrO₂	0.3 - 10	2.20, (0.30) 2.12, (0.35) 2.10, (0.40) 2.05, (0.5 - 2.0)	E-beam Graphite	2200

Oxide notes: (a) Quarter-wave thickness exhibits <2% absorption; (b) Index corresponds to wavelength listed, IAD increases oxide indices by 1.04x; (c) Evaporation temperature at pressure near 1 E-04 torr; (d) Approximate density in film form. ARC is antireflection coating.

Deposition Parameters

Application Notes

Density (gm/cc) see noted)	Rate (A/s)	Substrate Temp. (°C)	Pressure Oxygen (torr)	Combine with	Comments
3.6	2	250	~1 E-05	SiO₂, Sc₂O₃	UV laser ARC and high reflectors. Mirror protection.

5.2	5	~200-300	5 E-05	Glass, Si, Ge	Very hard, resistant to acids and alkalis; sunglass coating. Binding layer 10 nm.

9.7	2	150 - 250	2 - 5 E-05	Glass, SiO₂, Oxides	UV laser multilayers; high damage threshold 355 nm. IR mirror overcoat; emitter wire coating.

7.2	2	250	1 E-04	SiO₂, Glass, InSb, MgF₂	Hard, protective coating for metal mirrors.

7.2	3	350	1 E-04	SiO₂, Glass	Transparent conductor: electro-optic panels, displays. Sn doping availability.

7.2	3	~250	2 E-04	Glass, CeF₃	High-index, wide-band multilayers, VIS ARC, hard films. Requires post air-bake unless IAD.

6.9	3	300	1 E-04	Oxides	Component in wide-band VIS ARC. Does not disassociate.

3.8	3	200 - 250	1 E-04	MgF₂, SiO₂	UV ARC 248 nm. ARC on high- damage semiconductors. Threshold at 355 nm with MgF₂.

2.1	5	200	5 E-05	Oxides, CeF₃	Amorphous vitreous films. High rate or low substrate temperatures product stressed, underdense films.

2.0	10	100 - 150	2 E-06	Oxides, Si, Ge, Al	Protecton of Al and Ag mirrors; ARC Si; low tensile stress, amorph. high density; component or IR multilayers to 5 µm.

8.7	2.5	175 - 300	2 E-04	SiO₂	VIS and NIR filters; hard protective films; 1064- nm laser coatings.

4.0	5	250	1 - 2 E-04	SiO₂, Oxides	Amorphous below 300 °C, crystalline above 300 °C. Durable multilayers; protective coating, saltwater-resistant. high tensile stress.

4.5	3	150 - 300	1 E-04	Oxides, Fluorides, Ag, Al	IR mirror overcoat; wide-band VIS ARC layer. Water absorption bands at low temperature.

5.0	3	200 - 300	1 E-04	SiO₂, Oxides	VIS multilayers, high damage threshold to 350 nm, hard films, inhomogeneous index gradient, modifications available.

Identification

Physical Parameters

Material Name	Material Formula	Transparent Region(µm) (see note a)	Index at Wavelength (µm) (see note b)	Method/ Holder	Evap. Temp. °C) (see note c)
FLUORIDES
Aluminum Fluoride	AiF₃	0.2 - 12	1.36, (0.60) 1.34, (1.00) 1.30, (8 - 10)	Resistance, E-beam Graphite	1100

Calcium Fluoride	CaF₂	0.15 - 12	1.35, (0.2 - 10)	Resistance Ta, Mo	1200

Cerium Fluoride	CeF₃	~0.3 - 11	1.62, (0.50) 1.60, (1.00) 1.44, (8 - 10)	Resistance E-beam Ta, Mo	1300

Lanthanum Fluoride	LaF₃	0.25 - 11	1.64, (0.30) 1.60, (0.50) 1.35, (10.00)	Resistance Mo, Ta	1300

Magnesium Fluoride	MgF₂	0.15 - 6	1.42, (0.30) 1.39, (0.40) 1.38, (0.55) 1.36, (0.80)	Resistance	950

Thorium Fluoride	ThF₄	0.25 - 14	1.55, (0.55) 1.40, (5 - 8) 1.36, (8 - 12)	Resistance E-beam Ta	800

Yttrium Fluoride	YF₃	0.25 - 11	1.45, (5.00) 1.30, (10.00)	Resistance Alumina	800

FLUORIDES NOTES: Rates for all fluorides are 10 - 20 A/S; pressure ~5 E-05 torr.


INFRARED MATERIALS
Cadmium Telluride	CdTe	0.9 - 25	2.65, (1 - 10)	Resistance, Alumina, Mo	900

Germanium	Ge	2.0 - 12	4.10 - 400, (>2)	E-beam Ta, Graphite, Alumina	1600

Lead Telluride	PbTe	3.5 - 80 (300K) 7 - 80 (77 K)	5.40, (5 - 10)	Resistance Alumina, Graphite	1100

Silicon	Si	1.1 - 8	3.40, (>1.2)	E-beam Ta, Graphite	1300

Zinc Selenide	ZnSe	0.6 - 16	2.60, (0.60) 2.50, (1.00) 2.35, (5 - 10)	Resistance Silica, Ta, Mo	900

Zinc Sulfide	ZnS	0.4 - 14	2.50, (0.40) 2.35, (0.60) 2.25, (1.00) 2.15, (5 - 12)	Resistance Ta, Silica, Mo	1000

IR MATERIALS NOTES: Rates ~5 A/s; pressure <1 E-05 torr.

Deposition Parameters

Application Notes

Density (gm/cc) see noted)	Substrate Temp. (°C)	Combine with	Comments
2.9	250 - 300	Fluorides, ZnS, ZnSe	AR UV-IR excimer laser.

3.0	200	Sc₂O₃, ZnSe	UV-IR, UV laser coatings, low packing density, hygroscopic.

6.0	250	ZnSe,ZnS, Fluorides	Amorphous, hard, water- resistant, IRX^TM formulation replacement for the ThF₄.

5.8	300	ZnS, ZnSe, Ge	Low index UV-IR, insoluble.

3.1	250 - 300	Fluorides, Glass	Lowest index, multilayers, tensile stress, low packing density at low substrate temperature, absorbs water.

8.2	200 - 250	ZnS, ZnSe, Ge	High damage threshold 10.6 µm, radioactive: dust is hazardous.

8.0	200 - 250	ZnSe, Ge, ZnS	IR multilayers. Low water absorption. ThF₄ replacement.


6.0	150	ZnSe	IR multilayers, soft.

5.3	150		Filters.

8.1	150	ZnS, ZnSe	Far-IR multilayers, filters. Requires gentle preheating and evaporation.

2.3	150	SiO, Oxides	Hard films, SWIR filters.

5.2	150	Fluorides, Ge, CeF₃	AR multilayers. Decomposes and reassociates.

3.8	150	Fluorides, Ge, CeF₃	AR multilayers. Decomposes and reassociates.

SOURCE: CERAC, inc. with technical assistance from Pellicori Optical Consulting

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