K.M. Strohm

Silicon High Resistivity Substrate Millimeter-Wave Technology

The application of the VLSI-techniques molecular beam epitaxy (MBE) and X-ray lithography for the fabrication of monolithic integrated millimeter-wave devices on high resistlvity silicon has been investigated. Process compatibility and the retention of high resistivity characteristics were measured using the spreading resistance method and Hall measurements after various process steps. Ring- and linear microstrip resonators were fabricated on 10 000 Ohm cm silicon. For linear microstrip resonators, the attenuation was found to be less than 0.6 dB/cm at 90 GHz. A 95 GHz impatt oscillator has been integrated on a highly insulating silicon substrate in a combined monolithic-hybrid technique. The oscillator needs no tuning elements. From preliminary experimental results 8 mW output power with 0.2 % efficiency at 95 GHz oscillating frequency has been obtained.The application of molecular beam epitaxy (MBE) and X-ray lithography for the fabrication of monolithic integrated millimeter-wave devices on high-resistivity silicon has been investigated. Process compatibility and the retention of high-resistivity characteristics were measured using the spreading resistance method and Hall measurements after various process steps. Microstrip resonators of ring and linear geometry were fabricated on 10 000 Ω.cm silicon substrates. For linear microstrip resonators, the attenuation was found to be less than 0.6 dB/cm at 90 GHz. A 95-GHz IMPATT oscillator circuit and a planar microstrip antenna array have been fabricated on highly insulating silicon substrates. For the oscillator, a combined monolithic-hybrid integration technique was used to attach the discrete IMPATT diode to the resonator circuit. The oscillator does not require tuning elements. Preliminary experimental results are 8 mW of output power with 0.2 percent efficiency at 95 GHz.

Si/SiGe MMIC's

Silicon-based millimeter-wave integrated circuits (SIMMWICs) can provide new solutions for near range sensor and communication applications in the frequency range above 50 GHz. This paper presents a survey on the state-of-the-art performance of this technology and on first applications, The key devices are IMPATT diodes for MM-wave power generation and detection in the self-oscillating mixer mode, p-i-n diodes for use in switches and phase shifters, and Schottky diodes in detector and mixer circuits. The silicon/silicon germanium heterobipolar transistor (SiGe HBT) with f/sub max/ values of more than 90 GHz is now used for low-noise oscillators at Ka-band frequencies. First system applications are discussed. >

Coplanar passive elements on Si substrate for frequencies up to 110 GHz

This paper provides both modeling and design information on coplanar passive elements on a silicon substrate. The influence of substrate resistivity on coplanar waveguide (CPW) loss is discussed, and elements of a cell library for coplanar monolithic microwave integrated circuits (MMICs) on high-resistivity substrates are presented. The elements include discontinuities, junctions, and spiral inductors. The models are based on field-theoretical simulations and verified by S-parameter measurements up to 110 GHz.

SIMMWIC rectennas on high-resistivity silicon and CMOS compatibility

Rectifying antennas (rectennas) are realized on high-resistivity silicon substrates using silicon monolithic millimeter-wave integrated circuit (SIMMWIC) technology. Monolithically integrated coplanar Schottky barrier diodes are used as rectifying elements embedded in different antenna structures. Both p- and n-type Schottky barrier diodes are realized with cutoff frequencies up to 1 THz. The rectennas are combined with a CMOS preamplifier mounted as a multichip module (MCM) next to the rectenna on a high-resistivity silicon substrate. An amplification of 32 dB is measured. Maximum sensitivity of the detector circuit including preamplification is 1600 mV/mW/spl middot/cm/sup -2/ at 94.6 GHz. For a monolithic integration of high-frequency circuits with low-frequency control and signal-processing electronics, the monolithic integration of CMOS circuitry on high-resistivity silicon is discussed.

Active SIMMWIC-antenna for automotive applications

An active SIMMWIC-Antenna (Silicon Monolithic Millimeterwave Integrated Circuit) for vehicular technology in the frequency range around 76.5 GHz is presented. This active antenna acts as a transceiver and is well suited for low-cost integrated sensor systems for automotive applications. The monolithic active antenna embedded in a synchronization network requires only 3.2/spl times/2.6 mm/sup 2/ chip size. Using subharmonic injection locking frequency tuning and stabilization is realized. With an injection power of 0 dBm we measured a tuning range of 300 MHz. To our knowledge, this is the first synchronizable monolithic integrated active antenna suited for automotive applications in the frequency band around 76.5 GHz.

47 GHz SiGe-MMIC oscillator

A 47 GHz MMIC SiGe-HBT oscillator on high-resistivity silicon is presented. An output power of 13.1 dBm and an efficiency of 13.6% is measured. The oscillator exhibits a phase-noise of -99.31 dBc/Hz at 100 kHz off-carrier. These results represent a new record value for SiGe-HBT based oscillators.

A monolithic integrated millimeter wave transmitter for automotive applications

An integrated transmitter at 80 GHz is presented. This device finds many applications in civil sensor and communication systems, and is employed in automotive applications. The device consists of an IMPATT diode and a slotted patch resonator. The resonator acts simultaneously as an antenna. The resonator impedance seen by the IMPATT diode is calculated by means of a full wave analysis and the matching of the IMPATT diode is investigated using a large signal analysis. The transmitter devices have been fabricated employing a SIMMWIC (silicon millimeter wave integrated circuit) fabrication process and deliver a radiated power of up to 1 mW at 79 GHz. An excellent carrier-to-noise ratio of 81.7 dBc/Hz at an offset of 100 kHz has been achieved. The deviation of the measured values from the theoretically predicted values of frequency and power is -5.9% and -1.5 dB, respectively. >

RF-MEMS switching concepts for high power applications

RF MEMS switches for power applications are discussed in this paper. Mechanical and electromagnetic simulations of a new switch type for power applications are presented, and fabrication aspects are discussed.

A SIMMWIC 76 GHz front-end with high polarization purity

An integrated active antenna with a polarization purity better than 28 dB and a radiated power of 8 dBm at 75.7 GHz is presented. The linearly polarized radiator consists of a planar resonant antenna and a transit-time diode monolithically integrated on a silicon substrate. This active antenna finds various applications in low-cost multi-channel sensor systems, e.g. for object classification. Guidelines for the design are discussed. The characterization of the fabricated SIMMWIC devices includes measurements of output power, polarization purity, and far-field pattern. Moreover, the oscillation frequency of the devices has been successfully stabilized using subharmonic injection locking. The FM noise behavior of the locked oscillator has been characterized. The measured results are presented and compared to theoretical calculations.

Via hole technology for microstrip transmission lines and passive elements on high resistivity silicon

A process is described for the realization of via holes for microstrip transmission lines and passive elements on high resistivity silicon (/spl rho/>4000 /spl Omega/cm, 100 mm diameter, 100 /spl mu/m thickness). Via hole etching with vertical sidewalls is performed using an advanced silicon etch (ASE) process. The measured and simulated inductance of the gold metallized via hole is 22 pH. Measurements on a ring resonator-isolated by 550 nm thermal oxide from the substrate-yield a dielectric constant /spl epsiv//sub r/=11.2 and a loss tangent tan/spl delta/ around 10/sup -4/ for the 4000 /spl Omega/cm silicon substrate. Attenuation of microstrip transmission lines are <0.1 dB/mm at 20 GHz.