K. T. Chan

Integrated antennas on Si, proton-implanted Si and Si-on-quartz

High performance antennas have been realized on proton-implanted Si with 10/sup 6/ /spl Omega/-cm resistivity. Sharp antenna resonance and low loss up to 20 GHz are observed indicating excellent antenna quality. In contrast, very poor antenna characteristics are found on conventional oxide-isolated Si because of the lossy substrate.

Integrated antennas on Si with over 100 GHz performance, fabricated using an optimized proton implantation process

We have improved the performance of integrated antennas on Si for possible application in wireless communications and wireless interconnects. For practical VLSI integration, we have reduced the antenna size and optimized the proton implantation to a low energy of /spl sim/4 MeV with a depth of /spl sim/175 /spl mu/m. To avoid any possible contamination, the ion implantation is applied after device fabrication. Excellent performance such as very low RF power loss up to 50 GHz, record high 103 GHz antenna resonance, and sharp 5 GHz bandwidth have been achieved.

40-GHz coplanar waveguide bandpass filters on silicon substrate

We report a very simple process to fabricate high performance filter on Si at 40 GHz using proton implantation. The filter has only -3.4-dB loss at peak transmission of 40 GHz with a broad 9-GHz bandwidth. In sharp contrast, the filter on 1.5-/spl mu/m SiO/sub 2/ isolated Si has much worse transmission and reflection loss. This is the first demonstration of high performance filter at the millimeter-wave regime on Si with process compatible with current VLSI technology.

Frequency-dependent capacitance reduction in high-k AlTiO x and Al 2 O 3 gate dielectrics from IF to RF frequency range

We have characterized the capacitance and loss tangent for high-k Al/sub 2/O/sub 3/ and AlTiO/sub x/ gate dielectrics from IF (100 KHz) to RF (20 GHz) frequency range. Nearly the same rate of capacitance reduction as SiO/sub 2/ was demonstrated individually by the proposed Al/sub 2/O/sub 3/ and AlTiO/sub x/ gate dielectrics as frequency was increased. Moreover, both dielectrics preserve the higher k better than SiO/sub 2/ from 100 KHz to 20 GHz. These results suggest that both Al/sub 2/O/sub 3/ and AlTiO/sub x/ are suitable for next generation MOSFET application into RF frequency regime.

Transmission line noise from standard and proton-implanted Si

We have measured the NF/sub min/ of transmission lines on 10/sup 6/ ohm-cm proton implanted Si, Si-on-Quartz, and standard Si with top isolation oxide. Transmission lines on proton implanted Si shows the lowest NF/sub min/ of less than 0.2 dB because of the low substrate loss due to the high resistivity. The proton implantation did not contribute to excess shot noise induced by carrier trapping and de-trapping because of the very small diffusion length to metal line.

RF passive devices on Si with excellent performance close to ideal devices designed by electro-magnetic simulation

High quality RF inductors, very low loss and noise CPW and microstrip lines, advanced broad and narrow band filters, and ring resonators have been achieved on Si substrates, using an optimized proton implantation process. The RF performance up to 100 GHz is close to that for ideal devices designed by EM simulation for lossless substrates.

Large Q-factor improvement for spiral inductors on silicon using proton implantation

We have improved the Q-factor of a 4.6 nH spiral inductor, fabricated on a standard Si substrate, by more than 60%, by using an optimized proton implantation process. The inductor was fabricated in a 1-poly-6-metal process, and implanted after processing. The implantation increased the substrate impedance by /spl sim/ one order of magnitude without disturbing the inductor value before resonance. The S-parameters were well described by an equivalent circuit model. The significantly improved inductor performance and VLSI-compatible process makes the proton implantation suitable for high performance RF ICs.

Narrow-band band-pass filters on silicon substrates at 30 GHz

Using optimized ion implantation, we have fabricated high performance 2-pole and 3-pole CPW filters on Si substrates at /spl sim/30 GHz, with very narrow 1.0 (3.1%) GHz and 0.75 (2.5%) GHz pass-band as well as small insertion loss. Microstrip filters on Si show small 3.2 dB loss at 27 GHz, which has smaller size than CPW case without the large coplanar ground planes. In contrast, the nonimplanted filters failed due to the high substrate loss.

The minimum noise figure and mechanism as scaling RF MOSFETs from 0.18 to 0.13 /spl mu/m technology nodes

As scaling down the RF MOSFET from 0.18 to 0.13 /spl mu/m technology nodes, the f/sub T/ increases but the NF/sub min/ becomes worse by increasing /spl sim/0.2 dB. A small NF/sub min/ of 0.93 dB is measured at 5.8 GHz in 0.18 /spl mu/m MOSFET using 50 fingers but increases as either increasing or decreasing finger number. This abnormal dependence and higher noise at 0.13 /spl mu/m is accurately analyzed by equivalent circuit model and due to the combined gate resistance and substrate effect.

Low RF noise and power loss for ion-implanted Si having an improved implantation process

Very-low-transmission line noise of <0.25 dB at 18 GHz and low power loss /spl les/0.6 dB at 110 GHz have been measured on transmission lines fabricated on proton-implanted Si. In contrast, a standard Si substrate gave much higher noise of 2.5 dB and worse power loss of 5 dB. The good RF integrity of proton-implanted Si results from the high isolation impedance to ground, as analyzed by an equivalent circuit model. The proton implantation is also done after forming the transmission lines at a reduced implantation energy of /spl sim/4 MeV. This enables easier process integration into current VLSI technology.