W. J. Lin

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.

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.

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.

Low RF loss and noise of transmission lines on Si substrates using an improved ion implantation process

Very low power loss /spl les/0.6 dB at 110 GHz and noise of <0.25 dB at 18 GHz have been measured on transmission lines fabricated on Si substrates and implanted with protons. In contrast, a much worse power loss of 5 dB and higher noise of 2.5 dB were measured without implantation. This large improvement arises from the high resistivity by proton implantation, which was also done after forming the transmission lines and at a reduced energy of /spl sim/ 4 MeV for easier process integration into current VLSI technology.

High-performance microwave coplanar bandpass and bandstop filters on Si substrates

High-performance bandpass and bandstop microwave coplanar filters, which operate from 22 to 91 GHz, have been fabricated on Si substrates. This was achieved using an optimized proton implantation process that converts the standard low-resistivity (/spl sim/10 /spl Omega//spl middot/cm) Si to a semi-insulating state. The bandpass filters consist of coupled lines to form a series resonator, while the bandstop filter was designed in a double-folded short-end stub structure. For the bandpass filters at 40 and 91 GHz, low insertion loss was measured, close to electromagnetic simulation values. We also fabricated excellent bandstop filters with very low transmission loss of /spl sim/1 dB and deep band rejection at both 22 and 50 GHz. The good filter performance was confirmed by the higher substrate impedance to ground, which was extracted from the well-matched S-parameter equivalent-circuit data.

Microwave coplanar filters on Si substrates

High performance band-pass and band-stop microwave coplanar filters operating from 22 to 94 GHz have been realized on Si substrates using a proton implantation process. Very good insertion loss and filter characteristics close to ideal EM simulation are measured that demonstrate excellent filter performance to 91 GHz.

RF passive devices on Si substrates with close to ideal EM performance

RF passive devices, such as transmission lines, inductors, antennas and band-pass filters, fabricated on Si substrates, show performance close to that obtained by E-M simulations, from 1 to 110 GHz. This was achieved using an optimized /spl sim/4 MeV proton implantation process performed after device fabrication to avoid contamination and can be masked by photoresist.