Maureen Y. Lau

Design and characterization of multilayer spiral transmission-line baluns

We discuss the design of coupled spiral transmission-line baluns modeled after the Marchand type. The balun structure consists of a pair of coupled spiral conductors vertically offset across intervening polyimide layers. The baluns are fabricated on various substrates (glass and high- and low-resistivity silicon). The characteristics such as return loss, insertion loss, and output signal imbalance are measured. The center frequencies of 3-dB bandwidths (BWs), primarily determined by their conductor lengths, range from 1.2 to 3.5 GHz. The 3-dB BW normalized by the center frequency is /spl sim/1.48 in all cases. We observe an optimum BW for better performance. Return losses at the center frequencies range from 13 to 18 dB. Amplitude imbalance distributes in the range of 0.3-1.0 dB, depending on the sizes of devices and substrates. The minimum insertion loss is 0.55 dB for the balun on a glass substrate with 100-/spl mu/m-wide conductors. The devices fabricated on glass and high resistivity (>4000 n cm) silicon show remarkably similar behaviors despite the large difference in dielectric constant. This technique is applicable to monolithic microwave integrated circuits.

Silicon-on-silicon MCMs with integrated passive components

The authors evaluate a prototype silicon-on-silicon multichip module for potential use in cost-driven applications. The incorporation of integrated passive components, resistors and capacitors, in the module substrate is a significant advantage in many of these kinds of applications. A module has been built that incorporates both linear and bipolar and digital CMOS circuits. The unique features of the module are discussed, as well as the properties and performance limits of the resulting passive components.<<ETX>>

High Q-factor inductors integrated on MCM Si substrates

High quality factor (Q) inductors were designed and fabricated on high-resistivity (2000 /spl Omega//spl middot/cm) Si substrates with multichip module (MCM) fabrication technology. A Q-factor of 30 was achieved for an inductor of 4 nH at 1-2 GHz. To enhance the Q-factor and reduce the parasitic coupling capacitance, a staggered double metal-layered structure was utilized by taking advantage of the double-layered metal lines in MCM. With electromagnetic simulation tools, computer-aided analysis was used to optimize the device characteristics. The skin effect and the lossy substrate effect on the performance of the radio frequency (RF) thin-film inductors were studied. The fabrication process used polyimide as the dielectric layer and aluminum as the metal layer. The use of the low dielectric-constant material, polyimide, reduces the parasitic coupling capacitance between metal lines and increases the quality factor and the self-resonant frequency for the RF integrated inductors.

A silicon-on-silicon multichip module technology with integrated bipolar components in the substrate

To address the needs of cost driven, mixed signal applications, we have developed a silicon-on-silicon technology that incorporates both passive and active devices in the module substrate. The technology combines a simple, double-diffused epitaxial bipolar technology with our thin-film MCMs. We describe the basic elements of the technology, typical active device properties and some examples of their use in a low-cost MCM.<<ETX>>

Trends in silicon-on-silicon multichip modules

Three example applications of silicon-on-silicon multichip modules are discussed: a module used in a parallel processor, a low-cost silicon module for a high-volume consumer product application, and a high-performance digital telecommunications module. These applications illustrate the changes occurring in this technology and the forces that are driving these changes.<<ETX>>

An I/O CMOS buffer set for silicon multichip module's (MCM)

A set of I/O CMOS buffers for MCM is described. When simulation results of the MCM buffers are compared against conventional standard cell CMOS buffers, several advantages emerge. The results indicate that the new buffers dissipate 5 times less power, reduce propagation delay from chip core to another core from 3-6 nsec, and increase the frequency of operation by 2.5 times when compared to conventional CMOS buffers. Actual measurements between these buffers confirm these simulation results.<<ETX>>

A 27 mW CMOS RF oscillator operating at 1.2 GHz

A low power dissipation oscillator circuit in CMOS has been fabricated. The circuit uses inductors and capacitors to form a tank circuit while cross-coupled MOS devices provide the positive feedback to sustain oscillations. The inductors are formed on glass and are solder bumped to the die. The measured power dissipation is 1/10 of the simulated CV/sup 2/F generated by conventional means.<<ETX>>

High quality-factor inductors integrated on Si multichip modules

We report high quality (Q) factor inductors fabricated on a high-resistivity (2000 /spl Omega/-cm) Si substrate with MCM technology. Q-factors of 30-40 were achieved for inductors of a few nH at 1 GHz.

A silicon-on-silicon MCM for voice recognition/telephone answering device

We have built and demonstrated a silicon-on-silicon multichip module for use in a cellular telephone. This module performs speaker-dependent voice recognition and also serves as a telephone answering device. It takes advantage of the miniaturization possible with MCM technology. Other important factors in the use of this approach are the fast design and fabrication cycle and the ability to readily integrate specialized CMOS processes into a single package.