Ge(Germanium) Single Crystals and Wafers
Single Crystal Germanium Wafer
PAM-XIAMEN offers 2”, 3”, 4” and 6” germanium wafer, which is short for Ge wafer grown by VGF / LEC. Lightly doped N and P type Germanium wafer can be also used for Hall effect experiment. At room temperature, crystalline germanium is brittle and has little plasticity. Germanium has semiconductor properties. High-purity germanium is doped with trivalent elements (such as indium, gallium, boron) to obtain P-type germanium semiconductors; and pentavalent elements (such as antimony, arsenic, and phosphorus) are doped to obtain N-type germanium semiconductors. Germanium has good semiconductor properties, such as high electron mobility and high hole mobility.
1. Properties of Germanium Wafer
1.1 General Properties of Germanium Wafer
|General Properties Structure||Cubic, a = 5.6754 Å|
|Density: 5.765 g/cm3|
|Melting Point: 937.4 oC|
|Thermal Conductivity: 640|
|Crystal Growth Technology||Czochralski|
|Doping available||Undoped||Sb Doping||Doping In or Ga|
|Resistivity, ohm.cm||>35||< 0.05||0.05 – 0.1|
|EPD||< 5×103/cm2||< 5×103/cm2||< 5×103/cm2|
|< 5×102/cm2||< 5×102/cm2||< 5×102/cm2|
1.2 Grades and Application of Germanium wafer
|Electronic Grade||Used for diodes and transistors,|
|Infrared or opitical Grade||Used for IR optical window or disks,opitical components|
|Cell Grade||Used for substrates of solar cell|
1.3 Standard Specs of Germanium Crystal and wafer
|Crystal Orientation||<111>,<100> and <110> ± 0.5o or custom orientation|
|Crystal boule as grown||1″ ~ 6″ diameter x 200 mm Length|
|Standard blank as cut||1″x 0.5mm||2″x0.6mm||4″x0.7mm||5″&6″x0.8mm|
|Standard Polished wafer(One/two sides polished)||1″x 0.30 mm||2″x0.5mm||4″x0.5mm||5″&6″x0.6mm|
- Special size and orientation are available upon requested Wafers
2. Specification of Germanium Wafer
2.1 Specification of Germanium Wafer of 2”,3”,4”and 6”size
|Conduction Type||n-type, p type, undoped|
|Dopant||Gallium or Antimony||—|
|Wafer Diamter||2, 3,4 & 6||inch|
|OF||EJ or US||—|
|Carrier Concentration||request upon customers|
|Resistivity at RT||(0.001~80)||Ohm.cm|
|Etch Pit Density||<5000||/cm2|
|Laser Marking||upon request||—|
|Surface Finish||P/E or P/P||—|
|Package||Single wafer container or cassette||—|
2.2 Germanium Wafer for Solar Cell
|4 inch Ge wafer Specification||for Solar Cells||—|
|Orientation||(100) 9° off toward <111>+/-0.5|
|Off-orientation tilt angle||N/A||—|
|Primary Flat Orientation||N/A||—|
|Primary Flat Length||32±1||mm|
|Secondary Flat Orientation||N/A||—|
|Secondary Flat Length||N/A||mm|
2.3 Ge Wafer (as an optical filter substrate for a longpass SWIR filter)
|Item||DSP Ge Wafer|
|Thickness||1.50mm +/- 0.10mm|
|Surface Process||Double-side polished; minimum 90mm dia. central clear aperture|
|Other Parameters||60-40 scratch-dig or better|
|Less than 2 arc minutes parallelism|
|Surfaces optically flat to within 1 fringe irregular per any 25mm dia. in the clear aperture|
2.4 Germanium Used as Thin FIR Window (PAM211121-GE)
4″ Germanium wafer with low plasma frequency, undoped ,175µm+/-25um. (100), single side polished.
3. Germanium Wafer Process
With the advancement of science and technology, the processing technique of germanium wafer manufacturers is more and more mature. In the production of germanium wafers, germanium dioxide from the residue processing is further purified in chlorination and hydrolysis steps.
1)High purity germanium is obtained during zone refining.
2)A germanium crystal is produced via the Czochralski process.
3)The germanium wafer is manufactured via several cutting, grinding, and etching steps.
4)The wafers are cleaned and inspection. During this process, the wafers are single side polished or double side polished according to custom requirement, epi-ready wafer comes.
5)The thin germanium wafers are packed in single wafer containers, under a nitrogen atmosphere.
4. Application of Germanium:
Germanium blank or window are used in night vision and thermographic imaging solutions for commercial security, fire fighting and industrial monitoring equipment. Also, they are used as filters for analytical and measuring equipment, windows for remote temperature measurement, and mirrors for lasers.
Thin Germanium substrates are used in III-V triple-junction solar cells and for power Concentrated PV (CPV) systems and as an optical filter substrate for a longpass SWIR filter application.
5. Test of Germanium Wafer:
The resistivity of the crystal germanium wafer was measured by Four Probe Resistance Tester, and the surface roughness of Germanium was measured by profilometer.
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