Hyun-Chul Bae

A 5.8 GHz mixer using SiGe HBT process

DSRC provides high speed radio link between Road Side Equipment and On-Board Equipment within the narrow communication area. In this paper, a 5.8 GHz down-conversion mixer for DSRC communication system is designed and fabricated using 0.8 ¿m SiGe HBT process technology and RF/LO matching circuits, RF/LO input balun circuits and IF output balun circuit are all integrated on chip. The measured performance is 7.5 dB conversion gain, ¿2.5 dBm input IP3, 46 dB LO to RF isolation, 56 dB LO to IF isolation, current consumption of 21 mA for 3.0 V supply voltage and the chip size of fabricated mixer is 1.9 mm × 1.3 mm.

1/f noise in Si/sub 0.8/Ge/sub 0.2/ pMOSFETs under Fowler-Nordheim stress

The 1/f noise in Si/sub 0.8/Ge/sub 0.2/ pMOSFETs was found to be lower than in all-silicon (Si) pMOSFETs, before and after Fowler-Nordheim (F-N) stress. The minimum noise in the Si/sub 0.8/Ge/sub 0.2/ pMOSFET occurred at the thinnest unconsumed Si-cap of approximately 2 nm, because of the reduced-oxide trap density (N/sub ot/) near the Fermi level (E/sub F/) in the device. However, all samples in this study, including the Si control and the Si/sub 0.8/Ge/sub 0.2/ pMOSFETs with different unconsumed Si-cap thicknesses of 21-64 /spl Aring/, revealed almost identical relative changes in 1/f noise due to the stress, despite the relatively wide range of initial noise values. This suggests identical relative changes in N/sub ot/ at the E/sub F/ in the devices during F-N stress.

A 1-6 GHz monolithic up-conversion mixer with input/output active baluns using SiGe HBT process

In this paper, a 1-6 GHz MMIC up-conversion mixer, for an RF transmitter, is designed and fabricated using 0.8 /spl mu/m SiGe HBT process technology. This mixer is implemented on-chip using LO/RF wideband matching circuits, LO/IF input balun circuits, and an RF output balun circuit. The measured results of the fabricated mixer show positive power conversion gain from 1 GHz to 6 GHz, bandwidth of 4.5 GHz, LO isolation (LO to IF isolation and LO to RF isolation) between 27 dB and 45 dB, OIP3 between -2 dBm and -12 dBm, current consumption of 29 mA for 3.0 V supply voltage. The chip size of the fabricated mixer is 2.7 mm/spl times/1.6 mm.

Improved quality and reliability of ultrathin (1.4–2.3 nm) gate oxides by radical-assisted oxidation utilizing a remote ultraviolet ozone source

A low-temperature and high-purity radical-assisted oxidation (RAO) process for the growth of ultrathin (1.4–2.3 nm) gate oxides was successfully developed utilizing a remote ultraviolet ozone source. The metal–oxide–semiconductor transistors with RAO gate oxides showed improved device characteristics and oxide reliability, in comparison with the devices with non-RAO or standard furnace oxides. The RAO process in this study was proven to be an effective technique to make the oxide network robust and dense, without an increase of growth temperature.

A 5.8 GHz up-conversion mixer for DSRC transmitter

DSRC provides high speed radio link between road side equipment and on-board equipment within the narrow communication area. In this paper, a 5.8 GHz up-conversion mixer for DSRC RF transmitter is designed and fabricated using our 0.8 /spl mu/m SiGe HBT process technology and IF/LO/RF matching, IF/LO input baluns and RF output balun are all integrated on chip. The measured performance is 3.5 dB conversion gain, -12.5 dBm output IP3, 42 dB LO to IF isolation, 38 dB LO to RF isolation, current consumption of 29 mA for 3.0 V supply voltage and the chip size of fabricated mixer is 2.7 mm /spl times/ 1.6 mm.

A 1.8 GHz fully differential VCO using SiGe BiCMOS process technology

In this paper, we fabricated a 1.8 GHz differential VCO using 0.5 /spl mu/m SiGe BiCMOS process technology. The fabricated VCO consumes 16 mA at 3 V supply voltage and has a 1.2/spl times/1.6 mm/sup 2/ chip area. A phase noise measured at 100 kHz offset carrier is -98 dBc/Hz and a tuning range is 1795 MHz /spl sim/1910 MHz when two varactor diodes are biased from 0 V to 3 V.