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This paper describes a 77-GHz three-stage driver amplifier integrated with a very compact 4-dB digital attenuator. The attenuator can provide successful suppression in the gain variation of the amplifier according to ambient temperature in practical use. In addition, the amplifier matching fashion using short stubs and series transmission lines helps suppress unwanted transducer gain and return gain in the out-of band of lower than 77 GHz. The amplifier fabricated in pseudomorphic high electron-mobility technology can deliver a gain of 17.9 dB with an input return loss of 21.0 dB and an output return loss of 22.7 dB in the 77-GHz band, while keeping lower than -16.5 dB of gain in the out-of band. Over the temperature range from -20[degrees]C to 100[degrees]C, the measured results show that a gain variation of less than 2.0 dB is achieved by using the attenuator, while the gain variation without the attenuator is as large as 6.0 dB. The die size is as small as 2.3 x 1.4 [mm.sup.2] due to the very compact attenuator of a 0.2 x 0.6 [mm.sup.2] occupied area. Index Terms--Amplifiers, attenuators, millimeter-wave amplifiers, minimization methods, radar applications, temperature.

Carbon nanotube probe and a highly sensitive dynamic measurement scheme has enabled us to use atomic force microscopy to measure oscillatory forces in water on approaching a surface that is laterally characterized on a nanometer scale. The study suggested that the action of a dehydrating agent or water-structure breaker might be chiefly on the nearby surface rather than on water.

Scanning tunneling microscopy and self-assembled techniques were used in measuring the electrical conductivity of organic molecules. The synthesized molecule (1,1':4,' 1'-terphenyl)-4 -methanethiol (TP) with three phenyl rings were used in the study. Results indicated that the TP molecules have protruding domains with heights that increase as the lateral size of the domain grows from 1 to 10 nm. This suggested that there was an increase in the vertical conductance due to the lateral, intermolecular interaction.

This paper reports on the excellent performance of V-band monolithic high electron-mobility transistor (HEMT) oscillators, and discusses oscillation characteristics on drain bias. With regard to output characteristics, double-hetero (DH) HEMT (especially with a high-density Si-planar doped layer) are superior to single-hetero (SH) HEMT's. A monolithic microwave integrated circuit (MMIC) oscillator has been developed with a planar doped DH HEMT and has achieved the peak output power of 11.1 dBm at a 55.9-GHz oscillation frequency. Phase noise of -85 dBc/Hz at 100-kHz offset and -103 dBc/Hz at 1-MHz offset have been achieved at a drain voltage of 5.5 V and a gate voltage of 0 V. These characteristics have been achieved without any buffer amplifiers or dielectric resonators. This study has revealed that the phase noise decreases as drain voltage increases. This phenomenon is caused by lower pushing figure and lower noise level at a low-frequency range obtained under a high drain voltage. It is because the depletion layer in the channel is extended to the drain electrode with increase of drain voltage, resulting in the small fluctuation of the gate-to-source capacitance. We also investigate low-frequency noise spectra of AlGaAs/InGaAs/GaAs DH HEMT's with different bias conditions. The low-frequency noise decreases for more than 3 V of the drain voltage. A unique mechanism is proposed to explain this phase noise reduction at high drain voltage. Index Terms - Drain bias, HEMT, MMIC's, phase noise.

A novel method of low-energy [N.sub.2] neutral beam (NB) irradiation is examined as a means of controlling the surface nitridation of self-assembled monolayers (SAMs). The results have indicated that the low-energy NB technique has caused less damage to modified surfaces than the conventional plasma process and hence it is a potential damage-free process for modifying the surfaces of soft organic materials and films.

A study is presented to demonstrate that the steadiness of a conductive bridge-structure depends on the molecular structure of the bridge molecule for nanogap junctions using three types of modified alpha,omega-bis(thioacetate) oligo(phenylene vinylene)s (OPVs). Results show that conjugated molecules consisting of methylthioacetate termini and short alkoxy side chains are well suited for fabricating a steady conductive bridge-structure between two facing electrodes.

The surface potential switching on gold(111) surfaces is induced by complexation/decomplexation reactions of a bipyridine (BP) derivative and palladium(II) chloride, as observed by Kelvin probe force microscopy (KFM). The dipole moment estimated by the surface potentials is much smaller than the calculated value, indicating that mechanisms for the reduction of the surface dipole moment exist in real monolayers prepared by the microcontact printing (CP) technique.

The electrical conduction of self-assembled monolayers (SAMs) made from conjugated molecules is measured using conductive atomic force microscopy (AFM), with a focus on the molecular structural effect on the electrical conduction. Using an insertion technique into insulative alkanethiol SAMs, single molecular resistance of terphenyl methanethiol at ca. 5.4 * 10(super 10) omega.

The study evaluated the electrical conduction of conjugated molecules by analyzing the dependence of the measured height of the conjugated molecular domains on their lateral sizes. To increase the vertical conduction of molecular domains, a methylene group is necessary between the sulfur and aromatic rings.