A linear electrostatic stepper motor has been designed and fabricated in a single mask surface micromachining process.. It consists of two drive units that alternately generate a step to move the shuttle. The friction and adhesion in the clamps has been measured. A friction coefficient of 0.8 * 0.3 have been found. The adhesion in the clamp is just low enough to release the clamping shoe. Stepping cycles have been performed succesfully to obtain a deflection of 15 pm, with steps in the order of 2 pm. The deflection is limited by the suspension. The generated force equals 3 pN at 40 V driving voltage.

Abstract-we have successfully fabricated and tested a high temperature superconducting sigma-delta A/D converter. The quantizer is a balanced comparator that has been characterized separately in two temperature regimes. The circuits have been fabricated with ramp edge junctions with a PrBaCuGaO-barrier on a buried ground plane. For the current to voltage conversion in the sigma-delta converter we fabricated a 50 mOhm resistor with an in-situ gold layer. The sigma-delta converter has been tested at an internal clock of up to 174 GHz. The signal-to-noise ratio has been measured at a relatively low frequency of 3.4 kHz and was at least 63 dB but most likely higher since the measurement was limited by the noise in the amplifiers. As a first attempt towards the development of a decimation filter we have fabricated and tested a toggle flip-flop. The toggle flip-flop has been tested successfully at 40 K up to a frequency of 33 GHz, which corresponds to 70 % of the Isn-product of a reference junction.h d e x Terms-Balanced comparator, oversampling, AD converter, toggle flip-flop.

We studied the morphology of ramps in YBa2Cu3O7-δ films and, subsequently, the barrier layer. The ramps have been fabricated by Ar ion beam milling using standard photoresist masks. SEM and AFM showed the formation of tracks along the slope of the ramp, originating from the irregular shape of the edge of the photoresist mask. A proposed modified reflowed resist and pre-annealing process show a significantly smoother ramp surface, important for the fabrication of reproducible Josephson junctions.

Abstract-We report on the characterization at high frequencies of DyBa2Cu307., thin film ramp-type junctions with a PrBazCuj07., barrier fabricated on MgO substrates using a thin SrTi03 buffer layer. Josephson emission has been detected over a wide temperature range from 4.2 K to 85 K at millimeter wavelengths using a sensitive receiver. Measured spectrum characteristics, emitted power and linewidth are well described by theoretical models. Signal frequency down conversion has been carried out in two different modes using external and internal local oscillators. Wide band electronically tunable Josephson emission allowed us to achieve the frequency down conversion in a very sensitive self-oscillator-mixing mode up to 2.5 THz. For the first time, for any type of Josephson junction, selfoscillator mixing has been achieved at ambient temperatures as high as 80 K.

Atomic force microscopy (AFM) is applied to study the surface morphologies and growth mechanisms of sputtered SrTiO 3 films on single-crystal MgO(100) substrates. Meanwhile, surface morphologies of as-polished and post-annealed MgO(100) substrates are investigated as well. Effects of the miscut (or misorientation) of the substrate surface on morphologies and growth mechanisms are discussed. For comparison, a typical surface morphology and growth mechanism of the spiral island structure in sputtered PrBa 2 Cu 3 O 7−δ films on MgO(100) substrates are presented.