Detail of GJB 2919A-2015

Introduction of GJB 2919A-2015

Specification for germanium used in infrared optics 1 Scope This specification specifies the requirements for germanium used in infrared optics. This specification is applicable to the germanium products used in infrared optics (hereinafter referred to as optical germanium) with wavelength range of 2.5~14.0μm. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this specification. For dated references, subsequent amendments (excluding corrections) to, or revisions, of any of these publications do not apply. However parties to agreements based on this specification are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references or references with version not indicated, the latest edition of the normative document referred to applies. GB/T 1550 Test methods for conductivity type of extrinsic semiconducting materials GB/T 6040 General rules for infrared analysis GB/T 6569 Fine ceramics (advanced ceramics, advanced technical ceramics) - Test method for flexural strength of monolithic ceramics at room temperature GB/T 26074 Germanium monocrystal - Measurement of resistivity-DC linear four-point probe GJB 179A-1996 Sampling procedures and tables for inspection by attributes YS/T 602 Test method for resistivity of zone-refined germanium ingot using a two-point probe 3 Requirements 3.1 Designation The designation of optical germanium is expressed as follows: Wherein, M represents monocrystal, P represents polycrystal, Cz represents Czochralski growth method and DS represents directional solidification method. Example: TR/Cz-MGe refers to germanium monocrystal used in infrared optics prepared by Czochralski growth method. 3.2 Electrical properties 3.2.1 Conductivity type The optical germanium is of n-type conductivity. 3.2.2 Resistivity The resistivity measuring temperature of optical germanium is (20±1)℃, and the common resistivity (ρ) is 5~30Ω·cm. Under specific conditions, the resistivity (ρ) is less than 5Ω·cm or greater than 30Ω·cm. 3.3 Optical properties 3.3.1 Transmittance The transmittance of optical germanium is as follows: a) At (20±3)℃, the transmittance curve of germanium monocrystal with resistivity (ρ) of 5~30Ω·cm and thickness of (5.0±0.1)mm is shown in Figure 1. The transmittance shall not be less than 39.5% at 2.5μm, not be less than 46% at 3.0~10.0μm, not be less than 45% at 11.0μm, not be less than 39.5% at 12.0μm, and not be less than 40.5% at 13.0~14.0μm. Figure 1 Transmittance curve of optical germanium monocrystal with resistivity of 5~30Ω·cm b) At (20±3)℃, the transmittance curve of germanium polycrystal with resistivity (ρ) of 5~30Ω·cm and thickness of (5.0±0.1)mm is shown in Figure 2. The transmittance shall not be less than 39.5% at 2.5μm, not be less than 46% at 3.0~10.0μm, not be less than 45% at 11.0μm, not be less than 39.5% at 12.0μm, and not be less than 40.5% at 13.0~14.0μm. Figure 2 Transmittance curve of optical germanium polycrystal with resistivity of 5~30Ω·cm c) See Figures 3 and 4 for transmittance curves of optical germanium monocrystals with resistivity of 1~5Ω·cm and resistivity greater than 30Ω·cm respectively. Figure 3 Transmittance curve of optical germanium monocrystal with resistivity of 1~5Ω·cm Figure 4 Transmittance curve of optical germanium monocrystal with resistivity greater than 30Ω·cm 3.3.2 Absorption coefficient At (20±3)℃, the absorption coefficients of optical germanium shall meet those specified in Table 1. Table 1 Absorption coefficient Absorption coefficient Wavelength μm 2.5 3.0 5.0 10.6 12.0 14.0 Absorption coefficient of monocrystal, cm-1 ≤0.035 ≤0.01 ≤0.015 ≤0.03 ≤0.035 ≤0.04 Absorption coefficient of polycrystal, cm-1 ≤0.04 ≤0.04 ≤0.025 ≤0.035 ≤0.04 ≤0.05 3.3.3 Refractive index See Table 2 for reference refractive index of optical germanium at (20±1)℃. Table 2 Refractive index of optical germanium Wavelength, μm Refractive index Permissible deviation 3.0 4.0444 ±0.0004 4.0 4.0243 5.0 4.0154 6.0 4.0106 7.0 4.0076 8.0 4.0057 9.0 4.0044 10.0 4.0035 10.6 4.0029 11.0 4.0025 12.0 4.0020 13.0 4.0014 14.0 4.0010 3.3.4 Refractive index inhomogeneity The refractive index inhomogeneity of germanium monocrystal shall be less than 5×10-5 and that of germanium polycrystal shall be less than 1×10-4 at a wavelength of 10.6μm. 3.3.5 Temperature coefficient of refractive index For optical germanium, the reference temperature coefficient of refractive index is (4±0.2)×10-4 at 20~25℃.   3.4 Bending fracture strength The bending fracture strength of optical germanium shall not be less than 75MPa. 3.5 Dimension and permissible deviation The dimension and permissible deviation of optical germanium shall be determined by the supplier and the purchaser through negotiation. 3.6 Appearance quality The corner angles, edges and all surfaces of optical germanium shall be free of gaps, cracks and holes that cannot be removed by subsequent processing. 4 Quality assurance 4.1 Inspection classification The inspections specified in this specification are quality conformance inspection. 4.2 Inspection conditions Unless otherwise specified, inspections shall be carried out under the following conditions: a) ambient temperature: 15~35℃; b) relative humidity: 45%~75%; c) atmospheric pressure: 76~106kPa. 4.3 Quality conformance inspection The quality conformance inspection of optical germanium may be classified into Group A inspection, Group B inspection and Group C inspection. See Table 3 for inspection items.

Contents of GJB 2919A-2015

Foreword i 1 Scope 2 Normative references 3 Requirements 4 Quality assurance 5 Delivery preparation 6 Instructions Annex A (Normative) Test method for transmittance and absorption coefficient of optical germanium in infrared waveband Annex B (Normative) Test method for refractive index of optical germanium Annex C (Normative) Test method for refractive index inhomogeneity of optical germanium