Jin-Young Kang

Cost Effective Parallel-branch Spiral Inductor with Enhanced Quality Factor and Resonance Frequency

In this paper, we present a cost effective parallel-branch spiral inductor with enhanced quality factor and resonance frequency. This structure is designed to improve the quality factor, but different from other fully stacked spiral inductors. The parallel-branch effect is increased by overlapping the first metal below the second metal with same direction. Measurement result shows an increased quality factor of 12% improvement. Also, we show an octagonal parallel-branch inductor which reduces parasitic capacitances for higher frequency applications

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 packaged. 2.3 GHz SiGe VCO with parallel-branch inductors

In this paper, a 2.3 GHz VCO with parallel-branch inductors was designed and fabricated using 0.8-/spl mu/m SiGe HBT process technology. Their Q-factors were higher than those of the conventional inductors. A good phase noise of -122 dBc/Hz was measured at 4 MHz offset frequency, and harmonics were suppressed by -28 dBc. The manufactured VCO core consumed 3.7 mA at 2 V supply voltage, and the VCO occupied 1.8 mm /spl times/ 1.2 mm chip areas.In this paper, a 2.3 GHz VCO with parallel-branch inductors was designed and fabricated using a 0.8-/spl mu/m SiGe HBT process technology. Their Q-factors were higher than those of the conventional inductors. A good phase noise of -122 dBc/Hz was measured at 4 MHz offset frequency, and harmonics were suppressed by -28 dBc. The manufactured VCO core consumed 3.7 mA at 2 V supply voltage, and the VCO occupied 1.8 mm /spl times/ 1.2 mm chip area.

Properties of WNx films and WNx/GaAs Schottky diodes prepared by ion beam assisted deposition technique

Low energy ion beam assisted deposition (IBAD) of refractory tungsten nitride films onto GaAs is attempted for the first time. This ion beam technique provides lower process pressure, and less ion damage to substrates and films than conventional reactive sputter deposition. Schottky diode characteristics of W/ and WNx/GaAs and their thermal stability were investigated by capping the refractory films with SiO2 films and subsequent annealing at 700–900 °C for 30 min. While both tungsten and tungsten nitride contacts were stable up to 850 °C, the tungsten nitride contact showed better thermal stability and higher Schottky barrier height. The Schottky barrier heights of W/ and WN0.27/GaAs diodes annealed at 850 °C were 0.71 and 0.84 eV, respectively. These preliminary results are comparable to those of the best results reported with the conventional sputtering methods.

A wideband fully integrated SiGe BiCMOS medium power amplifier

In this paper, a wideband 3.0 GHz-5.5 GHz medium power amplifier has been designed and fabricated using 0.8 /spl mu/m SiGe BiCMOS process technology. Passive elements such as parallel-branch spiral inductor, metal-insulator-metal (MIM) capacitor and three types of resistors are all integrated in this process. This medium PA is a two stage design with all matching components and bias circuits integrated on-chip. A P1 dB of 16.5 dBm has been measured with a power gain of 8.5 dB at 4.2 GHz with a total current consumption of 130 mA from a 2.5 V supply voltage at 25 /spl deg/C. The measured 3 dB bandwidth is 2.5 GHz, which is a very good result for a fully integrated medium PA. The fabricated circuit occupies a die area of 1.7 mm /spl times/ 0.8 mm.

A low-temperature and high-quality radical-assisted oxidation process utilizing a remote ultraviolet ozone source for high-performance SiGe/Si MOSFETs

By utilizing a remote ultraviolet ozone source, a low-temperature (600–700 °C) radical-assisted oxidation (RAO) process to produce high-quality ultrathin (1.4–3.7 nm) gate oxides was successfully developed for the fabrication of high-performance SiGe/Si metal-oxide-semiconductor field effect transistors (MOSFETs). The oxide grown by this technique showed much improved leakage and breakdown properties, compared with that grown without ozone. The reactive oxygen species in the RAO process seemed to cure the unpaired bonds in oxide networks making them more robust and dense, without an increase in thermal budget. The Si0.8Ge0.2 p-channel MOSFET with a RAO gate oxide exhibited superior device and 1/f noise characteristics to that with a standard higher temperature furnace oxide. This was because of the suppressed Ge-related gate-oxide degradation at the reduced process temperature when the Si-cap layer was thinned to below 2 nm. These suggest that the RAO process is particularly suitable for SiGe/Si MOSFET devices requiring a high-quality and low-temperature oxidation process.

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.

Enhanced fmax and Low Base Resistance in SiGe HBT with Nickel Silicidation

This electronic paper reports on our investigation of enhanced fmax and low base resistance of SiGe HBT, in which Ni silicidation is performed on the Si/SiGe/Si base instead of Ti silicidation. The properties of nickel silicidation on Si/SiGe/Si layer are compared with those of Ti silicidation. It is found that Ni silicidation affects the base resistance (RB) of SiGe HBT, where RB is a summation of the intrinsic base resistance (RINB) and the extrinsic base resistance (REXB). Comparing to the Ti silicided SiGe HBT, it shows about 10% enhanced fmax up to 41 GHz and above 70% reduced REXB of 9 Omega/square for Ni silicided SiGe HBT

High-quality epitaxial growth of in situ phosphorus-doped Si films by promoting dispersion of native oxides in α-Si

Two-step growth in reduced pressure chemical vapor deposition has been successfully developed to achieve in situ phosphorus-doped silicon epitaxial layers, and the characteristic evolution of their microstructures has been investigated using scanning electron microscopy, transmission electron microscopy, and secondary ion mass spectroscopy. The two-step growth, which employs crystallization of amorphous silicon (α-Si) layer grown at low temperature, offers crucial advantages in manipulating crystal structures of in situ phosphorus-doped silicon. Our experimental results suggest that an epitaxial or polycrystalline film is readily obtained by initiating growth either without or with annealing to crystallize the α-Si layers. Kinetic processes for crystallization were accompanied by stimulated dispersion of native oxides in α-Si buffers. We also observed that a high phosphorus doping level plays an important role in promoting the dispersion of native oxides, and that the shape of doping profiles depends upon the evolution of crystal structures with V-shaped defects. Thus, the phosphorus doping concentration remains uniform in high-quality single-crystalline Si films obtained by the two-step growth.