A 3-inch GaAs epitaxial wafer can be provided for making a PIN diode chip, which can make a power electronic device with high isolation and low insertion loss. A heterojunction AlGaAs/GaAs PIN wafer makes the diode with low RF on-state resistance suitable for fabricating various broadband switches. And these switches has excellent insertion loss and isolation from 50MHz to 80GHz. Compared with homojunction diode wafer structure, AlGaAs / GaAs PIN diode structure improves the performance in many microwave semiconductor applications. Here is a structure of GaAs PIN wafer for your reference:
1. Wafer Structure for AlGaAs PIN Diode
GaAs PIN wafer 3inch PAM170306-GAAS
|1||n-GaAs, Si doped||–||–|
|3||p-GaAs, Be doped||–||(1E18 cm^-3 +/-5%)|
|4||p-Al0.8Ga0.2As, Be doped||–||–|
|5||GaAs Substrate, 300-700um thick, p-doped, (001) orientation, flat orientation: |
2. Advantages of AlGaAs / GaAs PIN Epitaxial Wafer
Compared with the diode fabricated on homojunction GaAs wafer, the energy band difference produced by the AlGaAs / GaAs PIN diode structure heterojunction can effectively reduce the on-resistance of the diode, thereby reducing the insertion loss without changing the isolation. Therefore, the PIN diode based on heterojunction AlGaAs / GaAs structure has a greater advantage than the gallium arsenide PIN diode. Specifically：
- Compared with the equivalent GaAs PIN structure, the return loss, insertion loss and P-1dB index are improved;
- Discrete heterojunction AlGaAs PIN diodes exhibit a performance that reduces high-frequency insertion loss by a factor of two under a bias current of 10 mA.
3. Applications of AlGaAs / GaAs Epi Wafer
AlGaAs technology has used energy gap engineering to produce new semiconductor structures in the microwave industry for more than 20 years. Utilizing the various properties of multiple quantum wells, superlattices and heterojunctions, new types of semiconductors grown by molecular beam epitaxy and organometallic chemical vapor deposition have been manufactured. These bandgap principles have been applied to the development of AlGaAs technology, which has promoted a substantial improvement in the radio frequency performance of GaAs PIN photodiode.
Compound semiconductor pin switching diodes, like the AlGaAs PIN diode switches, have the characteristics of low on-resistance, small junction capacitance, bandwidth, easy integration, etc., and have been widely used in millimeter wave switching circuits. Among them, switching circuits and control circuits designed with GaAs-based pin switching diodes performed better.