Description

I. Core Product Value and Application Scenarios
Pseudomorphic High Electron Mobility Transistors (pHEMTs) are fabricated based on GaAs epitaxial materials. Leveraging excellent properties such as high electron mobility, high current modulation efficiency, and low loss, they are widely used in microwave, millimeter-wave, and other frequency bands. As the core material for pHEMTs, GaAs epitaxial wafers are also a critical component in the R&D and production of radio frequency (RF) chips for facial recognition, mobile phones, and base stations.
Our company provides pHEMT GaAs epitaxial wafers and customized services. Key performance indicators of our epitaxial wafers, including electron mobility, surface defect density, epitaxial material inhomogeneity, and two-dimensional electron gas (2-DEG) concentration, meet or exceed those of similar products from leading international GaAs enterprises, fully satisfying the requirements of high-end chip manufacturing.
II. Key Specifications of GaAs pHEMT Epitaxial Wafers
Size: 2–6 inches
Epitaxial Compounds: GaAs, AlGaAs, InGaAs, InAs
Doping Type: N-type doping, P-type doping
Composition Uniformity: >99%
2-DEG Concentration: >5×10¹²/cm²
Mobility: >6500 cm²/(V·s)
III. Characteristics of AlGaAs/InGaAs/GaAs pHEMT Epitaxial Structure
Taking the n⁺-AlₓGa₁₋ₓAs/i-InGaAs/i-GaAs pHEMT epitaxial heterostructure as an example, an undoped i-InGaAs layer is used as the channel layer. Due to the narrow bandgap of InGaAs, a large potential well depth (ΔEc) is formed at the n⁺-AlₓGa₁₋ₓAs/i-InGaAs heterojunction interface. This allows for a moderate reduction in the composition x of the n⁺-AlₓGa₁₋ₓAs control layer (to x<0.2), thereby avoiding the formation of DX centers. When x=0.15, ΔEc≈0.3 eV. This design of the n⁺-AlₓGa₁₋ₓAs/i-InGaAs modulation-doped heterojunction effectively eliminates the impact of DX centers, ensuring stable and excellent device performance. IV. Advantages of Pseudomorphic Modulation-Doped Heterojunction Field-Effect Transistors (pHEMTs) pHEMT is an improved structure of High Electron Mobility Transistors (HEMTs), also known as Pseudomorphic Modulation-Doped Field-Effect Transistors (PMODFETs). Its core advantages are as follows: Higher Electron Sheet Density: The two-dimensional electron gas (2-DEG) in pHEMTs is subject to dual confinement from both sides of the potential well, resulting in an electron sheet density approximately twice that of conventional HEMTs. Superior Electrical Performance: Combined with high electron mobility, GaAs pHEMT epitaxial devices offer greater current handling capability compared to conventional HEMT-based devices. They also feature low noise, higher output resistance, high transconductance, high operating frequency, and low power consumption, making them suitable for more complex high-frequency and low-power application scenarios.