GaN HEMT Epitaxial Wafer
Gallium Nitride (GaN) HEMTs (High Electron Mobility Transistors) are the next generation of RF power transistor technology. Thanks to GaN technology, PAM-XIAMEN now offer AlGaN/GaN HEMT Epi Wafer on sapphire or Silicon, and AlGaN/GaN on sapphire template.
GaN HEMT epitaxial wafer is a multilayer film grown epitaxially on a substrate, which usually includes a nucleation layer, a transition layer, a buffer layer, a channel layer, a barrier layer, a cap layer, and a passivation layer from bottom to top. The nucleation layer, like AlGaN or AlN, is used to prevent the substrate material from diffusing into the GaN epitaxial layer. The transition layer may contain hierarchical AlGaN, AlN/GaN superlattice or multilayer AlN to balance the stress between the GaN and the substrate. The higher the Al content in the barrier layer of AlGaN, the higher the 2DEG concentration at the heterojunction. Meanwhile, the lower the threshold voltage of the device, and the higher the current capacity. As the Al ratio increasing, the degree of heterogeneous crystal lattice mismatch will be higher, resulting in a decrease in gallium nitride HEMT electron mobility and a decrease in current capacity.
The High Electron Mobility Transistor (HEMT) is developed based on GaN with unique heterostructure and two-dimensional electron gas. The GaN HEMT advantages include high breakdown strength, low on-resistance and faster The switching speed, which is very suitable for medium and low voltage and medium and small power systems, such as travel adapters, wireless chargers, AC-DC converters, smart home appliances, etc. The epitaxial wafer with HEMT structure is more attractive currently for high-frequency converters, in which GaN HEMT breakdown voltage is 600~650 V. With the rapid development of gallium nitride HEMT epi technology, the price of GaN HEMT devices will be competitive, which can gain large GaN HEMT market for GaN HEMT manufacturers. Moreover, due to the gallium nitride HEMT reliability, it can be widely used in industrial fields, such as photovoltaic inverters, energy storage systems, and electric vehicles.
1. GaN HEMT Material: Available size:2”,4”,6”,8”:
More specific parameters of gallium nitride HEMT wafer for D-mode GaN HEMTs, E-mode GaN HEMTs, GaN HEMT power amplifier and RF, please refer to:
2. Now we show you an example as follows:
2.1 2″ (50.8mm)GaN HEMT Epitaxial Wafers
We offer 2″(50.8mm) gallium nitride HEMT Wafers, the GaN HEMT structure is as follows:
Structure(from top to bottom):
*undoped GaN cap(2~3nm)
* We can use Si3N to replace GaN on the top, the adhesion is strong, it is coated by sputter or PECVD.
2.2 AlGaN/GaN HEMT Epi Wafer on sapphire/GaN
|Layer #||Composition||Thickness||X||Dopant||Carrier Concentration|
2.3 2″(50.8mm),4″ (100mm)AlGaN/GaN HEMT Epi Wafer on Si
2.3.1 Specifications for Aluminium Gallium Nitride (AlGaN) / Gallium Nitride (GaN) High Electron Mobility Transistor (HEMT) on Silicon substrate.
|AlGaN/GaN HEMT Epi Wafer on Si|
|AlGaN/GaN HEMT structure||Refer 1.2|
|Growth method||Float Zone|
|Conduction Type||P or N|
2.3.2 Epi structure: Crack-free Epilayers
|Layer #||Composition||Thickness||X||Dopant||Carrier Concentration|
2.3.3 Electrical Properties of the AlGaN/GaN HEMT structure
2DEG Mobility (at 300 K) :≥1,800 cm2/V.s
2DEG Sheet Carrier Density (at 300 K) :≥0.9×1013 cm-2
RMS Roughness (AFM) : ≤ 0.5 nm (5.0 µm × 5.0 µm scan Area)
2.4 2″(50.8mm)AlGaN/GaN on sapphire
For specification of AlGaN/GaN on sapphire template, please contact our sales department: [email protected]
GaN HEMT Applications: Used in blue laser diodes, ultraviolet LEDs (down to 250 nm), and AlGaN/GaN HEMTs device.
3. Explanation of AlGaN/Al/GaN HEMTs:
Nitride HEMTs are being intensively developed for high-power electronics in high-frequency amplification and power switching applications. Often high performance in DC operation is lost when the HEMT is switched – for example, the on-current collapses when the gate signal is pulsed. It is thought that such effects are related to charge trapping that masks the effect of the gate on current flow. Field-plates on the source and gate electrodes have been used to manipulate the electric field in the device, mitigating such current-collapse phenomena.
4. GaN EpitaxialTechnology — Customized GaN epitaxy on SiC,Si and Sapphire substrate for HEMTs, LEDs:
5. GaN Device:
6. Test Characterization Equipment:
Contactless Sheet Resistance
Laser Thin Film Thickness Mapping
High Temp/High Humidity Reverse Bias
DIC Nomarski Microscope
Atomic Force Microscope (AFM)
Surface Defectivity Scan
High Temp Reverse Bias
4PP Sheet Resistance
Contactless Hall Mobility
X-ray Diffraction (XRD)/Reflectance (XRR)
7. Foundry Fabrication:
we also offer foundry GaN HEMT fabrication in the following process as follows:
Dry/Wet Metal/Dielectric Etch
Thin Film PECVD/LPCVD/Sputtering
Photolithography (0.35um min. CD)
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Float-Zone Mono-Crystalline Silicon
PAM-XIAMEN can offer float zone silicon wafer, which is obtained by Float Zone method. Monocrystalline silicon rods is got through float zone growth, and then process the monocrystalline silicon rods into silicon wafers, called float zone silicon wafers. Since the zone-melted silicon wafer is not in contact with the quartz crucible during the floating zone silicon process, the silicon material is in a suspended state. Thereby, it is less polluted during the process of floating zone melting of silicon. The carbon content and oxygen content are lower, the impurities are less, and the resistivity is higher. It is suitable for the manufacture of power devices and certain high-voltage electronic devices.
Ge(Germanium) Single Crystals and WafersPAM-XIAMEN offers 2”, 3”, 4” and 6” germanium wafer, which is short for Ge wafer grown by VGF / LEC. Lightly doped P and N 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.
SiC Wafer Substrate
The company has a complete SiC(silicon carbide) wafer substrate production line integrating crystal growth, crystal processing, wafer processing, polishing, cleaning and testing. Nowadays we supply commercial 4H and 6H SiC wafers with semi insulation and conductivity in on-axis or off-axis, available size:5x5mm2,10x10mm2, 2”,3”,4” and 6”, breaking through key technologies such as defect suppression, seed crystal processing and rapid growth, promoting basic research and development related to silicon carbide epitaxy, devices, etc.
Freestanding GaN substrate
PAM-XIAMEN has established the manufacturing technology for freestanding (gallium nitride)GaN substrate wafer, which is for UHB-LED and LD. Grown by hydride vapour phase epitaxy (HVPE) technology,Our GaN substrate has low defect density.