InP-based three-terminal electronic devices mainly include InP-based heterojunction bipolar transistors (HBTs) and high electron mobility transistors (HEMTs). PAM-XIAMEN can provide indium phosphide (InP) HEMT epi wafer, in which InGaAs use as the channel material and InAlAs as the barrier layer. The InP HEMT structure grown with InAlAs/InGaAs material system has very high carrier mobility, which can reach more than 10000cm2/Vs, and the band gap ranges from 0.7 to nearly 2.0 eV, which is conducive to band tailoring. InP based HEMT has the characteristics of high frequency, low noise, high efficiency, and radiation resistance, and become the preferred material for W-band and higher frequency millimeter-wave circuits. Please see the specific structure below:
1. InGaAs/InAlAs/InP HEMT Wafer
|Cap||In0.53Ga0.47As||–||Si (1×1019 cm-3)|
The higher the indium (In) composition of the InGaAs channel layer, the higher the peak saturation velocity, the greater the conduction band discontinuity with the InAlAs barrier layer, and therefore the higher the electron transfer efficiency, and the easier it will be in the InGaAs channel layer. The formation of two-dimensional electron gas with high concentration and high mobility will lead to better performance of InP HEMT device.
However, the lattice of the InGaAs layer matches the InP substrate only when the In composition is 0.53. When the In composition exceeds 0.53, the InGaAs and the InP substrate have lattice mismatch. Therefore, if the growth quality of the InGaAs layer is guaranteed to be good, its thickness must be less than the critical thickness during InP HEMT process. If the critical thickness is exceeded, lattice relaxation will occur in the InGaAs layer, and a large number of crystal defects, such as misfit dislocations, will be generated in the InGaAs channel layer. These crystal defects can greatly reduce electron mobility, thereby degrading the performance of HEMT devices.
Moreover, we can supply HEMT wafer epitaxy on GaAs and GaN substrate, for more information please read:
GaAs HEMT epi wafer: https://www.powerwaywafer.com/gaas-hemt-epi-wafer.html;
GaN HEMT epitaxial wafer: https://www.powerwaywafer.com/gan-wafer/gan-hemt-epitaxial-wafer.html.
2. Why InP HEMT Wafer Is Better Than GaAs HEMT Wafer?
In terms of substrate material, InP wafer has higher breakdown electric field, thermal conductivity and electron saturation velocity than GaAs. With the development and research of InP HEMT techonology, InP-HEMT has become a pillar product for high-end millimeter wave applications. The fT and fmax of the device reach 340GHZ and 600GHz respectively, which represents the highest level of three-terminal devices.
In addition, the excellent performance of InP-based HEMT wafer is directly derived from the intrinsic properties of the InAlAs/InGaAs material system. Compared with AlGaAs/GaAs HEMTs and AlGaAs/GalnAs pseudo-matched HEMTs, the performance of GalnAs/InAlAs HEMTs is much superior. For example, the electron mobility and saturation rate of the GaInAs channel are high, which results in superior transport properties. Moreover, due to the use of AlInAs as the electron supply layer, there is a large conduction band discontinuity (0.5 eV) at the InAlAs/InGaAs interface of the heterojunction, so it has the advantages of high electron mobility in the channel with large two-dimensional electron gas density. As a result, large current and high transconductance can be obtained, which makes the frequency characteristics of InP-HEMT better than that of GaAs-HEMT, especially in the band above 3 mm. The high transconductance of HEMT on InP substrate is directly related to increase operating frequency and outstanding gain-bandwidth characteristics.