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ABSTRACT: A low noise InGaP/InGaAs pseudomorphic high-electron-mobility transistor (PHEMT) with high IP3 was developed. The device utilises InGaP as the Schottky layer to achieve a low noise figure and uses AlGaAs as the spacer to reform the electron mobility and contains dual delta doped layers to improve the device linearity.
Electronics Letters 07/2004; · 0.96 Impact Factor
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ABSTRACT: A composite-channel metamorphic high electron mobility transistor (MHEMT) was developed for low noise high linearity application. The MHEMT was grown by molecular beam epitaxy (MBE) on GaAs substrates with InAlAs graded buffer. The composite-channel layers in the MHEMT include a top In<sup>0.55</sup>Ga<sup>0.45</sup>As layer, a middle In<sup>0.67</sup>Ga<sup>0.33</sup>As layer, and a bottom In<sup>0.55</sup>Ga<sup>0.45</sup>As layer. The design of this structure provides better electron confinement in the channel with less impact ionization as compared to conventional dual delta doped MHEMTs. This results in devices with higher linearity and drain to gate voltage as compared to the conventional metamorphic HEMTs. The 0.25×160μm<sub>2</sub> device with the novel channel structure exhibits a maximum frequency of oscillation f<sup>max</sup> of 290 GHz and a current gain cut-off frequency f<sup>t</sup> of 110 GHz. The noise figure of the device at 6 GHz is 0.23db and an associated gain was 15.06dB. The IP3 of the device at 6 GHz is 18.67dBm. The composite channel metamorphic HEMT shows great potential for high linearity and low noise application at high frequencies.
Electron Devices for Microwave and Optoelectronic Applications, 2003. EDMO 2003. The 11th IEEE International Symposium on; 12/2003
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ABSTRACT: The fabrication of phosphorus-based glasses containing Y3Fe5O12 crystals by the incorporation method was studied. From transmission electron microscopy observation, there is only one rod-like crystalline phase identified as Y3Fe5O12 existing in the glass matrix. When the content of YIG is 30 wt.%, the as-cast sample shows a Faraday rotation of 85°/cm and a magnetization of 0.4 emu/g in a field of 14 kOe. After heat treatment, the magnetic and optical properties of the glass ceramic changed owing to the thermal diffusion of iron ions into the glass matrix.
Journal of Alloys and Compounds 388(2):297-302. · 2.29 Impact Factor
