Germanium Wafer

Germanium Wafer

Single crystal Ge (Germanium) wafers grown by VGF / LEC can be offered by a germanium wafer manufacturer – PAM-XIAMEN.

Semiconductor devices fabricated on Ge wafer are used as diodes, transistors and composite transistors, and semiconductor optoelectronic devices on Germanium are used as photoelectric, Hall and piezoresistive sensors, photoconductive effect radiation detectors, etc. Most of the applications of Ge based semiconductor devices have been replaced by silicon. There is a certain amount of Ge crystal wafer used in high-frequency and high-power devices, while a large amount in photoelectric avalanche diodes.

Use single crystal Ge wafer to make a GaAs/Ge solar cell. The performance of Ge-based solar cell is close to that of a GaAs/GaAs cell, with higher mechanical strength and a larger monolithic cell area. In the space application environment, the anti-radiation threshold is higher than that of silicon cells, the performance degradation is small, and its application cost is close to the same power of silicon cell panels. Solar cell fabricated on bulk Ge substrate has been used in various types of military satellites and some commercial satellites, and has gradually become the main space power source. More about Ge single crystal wafer please see below:

Description

1. General Properties of Ge Wafer

General Properties Structure Cubic, a = 5.6754 Å
Density: 5.765 g/cm3
Melting Point: 937.4 °C
Thermal Conductivity: 640
Crystal Growth Technology Czochralski
Doping available Undoped Sb Doping Doping In or Ga
Conductive Type / N P
Resistivity, ohm.cm >35 < 0.05 0.05 – 0.1
EPD < 5×10^3/cm2 < 5×10^3/cm2 < 5×10^3/cm2
< 5×10^2/cm2 < 5×10^2/cm2 < 5×10^2/cm2

 

2. Grades and Application of Bulk Ge Substrate

Electronic Grade Used for diodes and transistors,
Infrared or opitical Grade Used for IR optical window or disks, optical components
Cell Grade Used for substrates of solar cell

 

3. Standard Specs of Ge Crystal and Wafer

Crystal Orientation <111>,<100> and <110> ± 0.5° 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

 

4. Special size and orientation are available upon requested germanium wafer:

4.1 Specification of Single Crystal Germanium Wafer

Item Specifications Remarks
Growth Method VGF  
Conduction Type n-type, p type, undoped  
Dopant Gallium or Antimony  
Wafer Diameter 2, 3, 4 & 6 inch
Crystal Orientation (100), (111), (110)  
Thickness 200~550 um
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  
Epi ready Yes  
Package Single wafer container or cassette  

 

4.2 Specification of Single Crystal Ge Wafer

4 inch Ge wafer Specification for Solar Cells  
Doping P  
Doping substances Ge-Ga  
Diameter 100±0.25 mm  
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
cc (0.26-2.24)E18 /c.c
Resistivity (0.74-2.81)E-2 ohm.cm
Electron Mobility 382-865 cm2/v.s.
EPD <300 /cm2
Laser Mark N/A  
Thickness 175±10 μm
TTV <15 μm
TIR N/A μm
BOW <10 μm
Warp <10 μm
Front face Polished  
Back face Ground  

 

5. Germanium Wafer Process

In the electronics grade and IR grade Ge wafer production process, 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 Ge crystal is produced via the Czochralski process;

3) The Ge 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 wafers are packed in single wafer containers, under a nitrogen atmosphere.

6. Germanium Applications

Germanium blank or window is used in night vision and thermographic imaging solutions for commercial security, firefighting 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 Ge single crystal wafers are used in III-V triple-junction solar cells and for power Concentrated PV (CPV) systems.

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