Enhancement-mode GaAs metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) with ex situ atomic-layer-deposited Al2O3 as gate dielectrics are studied. Maximum drain currents of 211 and 263mA∕mm are obtained for 1μm gate-length Al2O3 MOS-HEMTs with 3 and 6nm thick gate oxide, respectively. C-V characteristic shows negligible hysteresis and frequency dispersion. The gate leakage current density of the MOS-HEMTs is 3–5 orders of magnitude lower than the conventional HEMTs under similar bias conditions. The drain current on-off ratio of MOS-HEMTs is ∼3×103 with a subthreshold swing of 90mV/decade. A maximum cutoff frequency (fT) of 27.3GHz and maximum oscillation frequency (fmax) of 39.9GHz and an effective channel mobility of 4250cm2∕Vs are measured for the 1μm gate-length Al2O3 MOS-HEMT with 6nm gate oxide. Hooge’s constant measured by low frequency noise spectral density characterization is 3.7×10−5 for the same device.
This paper presents a polymer-based wafer-level integration technology suitable for integrating RF and mixed-signal circuits and systems. In this technology, disparate dies can be integrated together using a batch fabrication process. Very high density die-to-die interconnects with widths currently as small as 25 m are implemented. To demonstrate the capabilities of this technology, a 10-GHz receiver front-end implemented in 0.18-m CMOS technology is integrated with a high-resistivity Si substrate and embedded passives. By adjusting the input matching of the receiver using the embedded passives fabricated on the high-resistivity Si substrate, the input matching and conversion gain of the front-end receiver are improved.Index Terms-Heterogeneous integration, packaging, systemon-chip (SOC), system-on-package (SIP), wafer-scale integration.
InAs 1-x Sb x material with an alloy composition of the absorber layer adjusted to achieve 200K cutoff wavelengths in the 5 µm range has been grown. Compound-barrier (CB) detectors were fabricated and tested for optical response and J dark -V d measurements were acquired as a function of temperature. Based on absorption coefficient information in the literature and spectral response measurements of the midwave infrared (MWIR) nCBn detectors, an absorption coefficient formula α(Ε, x, T) is proposed.Since the presently suggested absorption coefficient is based on limited data, additional measurements of material and detectors with different x values and as a function of temperature should refine the absorption coefficient, providing a more accurate parametrization. Material electronic structures were computed using a k•p formalism. From the band structure, dark current density (J dark ) as a function of bias (V d ) and temperature (T) were calculated and matched to J dark -V d at fixed T and J dark -T at constant V d curves. There is a good match between simulation and data over a wide range of bias, but discrepancies that are not presently understood exist near zero bias.a. e-mail: arvind.d'
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