Browsing by Author "Lee, Ching-Sung"

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A novel dilute antimony channel In0.2Ga0.8AsSb/GaAs HEMT
(2007-02-01)
Su, Ke-Hua
;
Hsu, Wei-Chou
;
Lee, Ching-Sung
;
Wu, Tsung-Yeh
;
Wu, Yue-Han
This letter reports, for the first time, a high-electron mobility. transistor (HEMT) using A dilute antimony In0.2Ga0.8AsSb channel, which is grown by a molecular-beam epitaxy system. The interfacial quality within the InGaAsSb/GaAs quantum well of the HEMT device was effectively improved by introducing the surfactantlike Sb atoms during the growth of the InGaAs layer. The improved heterostructural quality and electron transport properties have also been verified by various surface characterization techniques. In comparison, the proposed HEMT with (without) the incorporation of Sb atoms has demonstrated the maximum extrinsic transconductance g(m,max) of 227 (180) mS/mm, a drain saturation current density I-DSS of 218 (170) mA/mm, a gate-voltage swing of 1.215 (1.15) V, a cutoff frequency f(T) of 25 (20.6) GHz, and the maximum oscillation frequency f(max) of 28.3 (25.6) GHz at 300 K with gate dimensions of 1.2 x 200 mu m(2).
Highly stable thermal characteristics of a novel In0.3Ga0.7As0.99N0.01 (Sb)/GaAs high-electron-mobility transistor
(2007-04-01)
Su, Ke-Hua
;
Hsu, Wei-Chou
;
Lee, Ching-Sung
;
Hu, Po-Jung
;
Hsia, Ru-Shang
A novel In0.3Ga0.7As0.99N0.01(Sb)/GaAs high-electron-mobility transistor has been successfully investigated for the first time by incorporating surfactant Sb atoms during the InGaAsN channel growth by molecular beam epitaxy (MBE). Superior stable thermal characteristics, including a thermal threshold coefficient (partial derivative V-th/partial derivative T) of -0.807 mV/K and a high-temperature linearity (partial derivative GVS/partial derivative T) of -0.053 mV/K, were achieved because of the improved crystalline quality and the enhanced carrier confinement capability of the In0.3Ga0.7As0.99N0.01(Sb)/GaAs heterostructure. The device also demonstrated a peak extrinsic transconductance (g(m,max)) of 94 (109) mS/mm at 450 (300) K.
Investigations on highly stable thermal characteristics of a dilute In(0.2)Ga(0.8)AsSb/GaAs doped-channel field-effect transistor
(2008-04-01)
Su, Ke-Hua
;
Hsu, Wei-Chou
;
Lee, Ching-Sung
;
Hu, Po-Jung
;
Wu, Yue-Han
This work reports for the first time a novel In(0.2)Ga(0.8)AsSb/GaAs heterostructure doped-channel field-effect transistor (DCFET) grown by the molecular beam epitaxy system. The interfacial quality within the InGaAsSb/GaAs quantum well of the DCFET device has been effectively improved by introducing surfactant-like Sb atoms during the growth of the Si-doped InGaAs channel layer. The improved device characteristics include the peak extrinsic transconductance (g(m, max)) of 161.5 mS mm(-1), the peak drain-source saturation current density (IDSS, max) of 230 mA mm(-1), the gate-voltage swing (GVS) of 1.65 V, the cutoff frequency (f(T)) of 12.5 GHz and the maximum oscillation frequency (f(max)) of 25 GHz at 300 K with the gate dimensions of 1.2 x 200 mu m(2). The proposed design has also shown a stable thermal threshold coefficient (partial derivative V(th)/partial derivative T) of -0.7 mV K(-1).