Effects of Si δ -Doping Condition and Growth Interruption on Electrical Properties of InP-Based High Electron Mobility Transistor Structures

Abstract

The InGaAs/InAlAs/InP high electron mobility transistor (HEMT) structures with lattice-matched and pseudomorphic channels are grown by gas source molecular beam epitaxy. Effects of Si 𝛿-doping condition and growth interruption on the electrical properties are investigated by changing the Si-cell temperature, doping time and growth process. It is found that the optimal Si 𝛿-doping concentration (𝑁 d ) is about 5.0 × 10 12 cm −2 and the use of growth interruption has a dramatic effect on the improvement of electrical properties. The material structure and crystal interface are analyzed by secondary ion mass spectroscopy and high resolution transmission electron microscopy. An InGaAs/InAlAs/InP HEMT device with a gate length of 100 nm is fabricated. The device presents good pinch-off characteristics and the kink-effect of the device is trifling. In addition, the device exhibits 𝑓T = 249 GHz and 𝑓max > 400 GHz.

Extrinsic equivalent circuit modeling of InP HEMTs based on full-wave electromagnetic simulation

“…The epitaxial layer structure is grown by molecular beam epitaxy (MBE) on a 3-inch (1 inch = 2.54 cm) semiinsulating (100) InP substrate. [13] The epitaxial layers consists of, from the bottom to the top, a 500-nm InAlAs buffer, a 15nm In 0.53 Ga 0.47 As channel layer, a 3-nm InAlAs spacer layer, an 8-nm InAlAs Schottky barrier layer, a 4-nm InP etching stopper layer, and a 20-nm Si-doped composite InGaAs cap layer. An Si-doped plane is inserted between the Schottky barrier layer and the spacer layer to supply the electrons for current conduction.…”

An overview of thermoelectric films: Fabrication techniques, classification, and regulation methods

“…In recent years, lots of strategies and concepts have been developed to enhance the electrical and thermal transport in films, including modulation doping, energy filtering, and band convergence. [12,13,26,37,39,[150][151][152] However, the interrelated relationship among TE parameters obstructs the improvement of TE performance, such as σ and S having an inverse relationship with the carrier concentration (n), the effective mass (m * ), and the carrier mobility (µ) making another mutually counter-indicated relations. For the sake of getting the maximum available zT and exploiting the full potential of a given TE material, Zhu et al [2] advanced that these advantageous strategies must be integrated to decouple electrical and thermal transport to optimize TE properties synergistically in the context of deep understanding of the underlying transport phenomena.…”

Growth condition optimization and mobility enhancement through inserting AlAs monolayer in the InP-based In x Ga 1− x As/In 0.52 Al 0.48 As HEMT structures

“…It would provide sufficient time for the migration of atoms on the growth surface to make the crystal interface smooth, which could reduce the interface roughness, remote impurity scattering, and alloy disorder scattering and increase the electron mobility. [15] But the different growth interruption time introduces a different density of undesired background impurities right at the InGaAs/InAlAs interfaces, which enhance the electron scattering and reduce the electron mobility. In order to study the effect of the growth interruption time on the 2DEG properties, a series of samples with different growth interruption times were grown at the substrate temperature of 475 • C. During the growth, all the other growth conditions and the structure parameters remained as discussed above.…”