A high precision nanoengineered device was developed to yield long term zero-order release of drugs for therapeutic applications. The device contains nanochannels that were fabricated in between two directly bonded silicon wafers and therefore poses high mechanical strength. The fabrication is based upon selectively growing oxide and then removing it, and thus defining nanochannels by consuming a specified layer of silicon during oxide growth. Diffusion through the nanochannels is the rate limiting step for the release of drugs. A measurement of glucose released through such nanochannels validates the zero-order release profile. Device design, fabrication details and the glucose release profile through 60 nm channels are presented.

The composition and annealing characteristics of plasma deposited silicon nitride encapsulating films on ion implanted gallium arsenide have been investigated. X-ray photoelectron spectroscopy was employed to study the surface of the semi-insulating GaAs substrates after cleaning in organic solvents, and HCt, HF, and NH4OH solutions prior to encapsulation. The composition of silicon nitride films deposited with 30 kHz RF excitation was determined through Auger electron spectroscopy and infrared spectroscopy as a function of the deposition conditions. Most of the films had a silicon to nitrogen ratio between 0.71 and 0.76 and a hydrogen concentration between 10 and 19%. GaAs substrates implanted with silicon at 100 keV to a dose of 5 • 1012 cm -2 and annealed at 800~ had peak electron concentrations of 1.7 • 1017 cm -3 at a depth of 0.1 ~m. High frequency encapsulated GaAs substrates implanted at 100 keV to a dose of 5 • 101~ cm -2 and 150 keV to a dose of 3 • 1012 cm -~ had peak electron concentrations of 1.7 • 1017 cm -3 and 9.6 • 101G cm 3 at depths of 0.1 and 0.12 ~tm, respectively. A Schottky-gate field effect transistor with a 3 ~m gate length which was fabricated using the silicon nitride encapsulant had a transconductance of 30 mS/ram.

phase noise = -68 dBc/Hz at 10 kHz from the carrier for the gold version. CONCLUSIONOur 12-GHz hybrid HTS/SC oscillator operating at 77 K exhibits a phase noise of -75 dBc/Hz at 10 kHz from the carrier, which is lower than the gold/SC one. A value of -68 dBc/Hz has been reported by Rohrer, Valco, and Bhasin [3] for a microstrip HTS/SC oscillator on a single substrate. It allows us to expect even improved performance for our oscillator, which will be quasiintegrated on a single substrate, with a transistor transplanted by expitaxial lift off or flip-chip techniques [4]. The design of the circuit packaging is also under study to avoid radiation losses. ACKNOWLEDGMENTSWe would like to thank J. C. Villegier and L. Arnaud from LET1 (Grenoble, France) for the deposition of the YBaCuO film A414 (sample B). ABSTRACTA time-frequency super-resolution procedure is presented for processing wideband backscattered data containing dispemwe surface-wave effects. This approach i s based on repeatedly applying the ESPRIT method to a sliding window of fiquency data. The mw poles returned by ESPRIT produce a more sharply resolved time-frequency &play than that of the short-rime Fourier transform. One inherent limitation of ESPRIT is that it findr a multitude of poles for a single disperswe scattering mechanism. l%is limitation is overcome by properly combining the mw poles comsponding to each disperswe mechanism This pok-combining approach recovers the hue frequency behavior of each disperswe mechanism and allows a complete parameter estimation of the data to be performed. ABSTRACTThe basic topology ir a series of transverse dipoles coupled electromagnetically to a microstrip line. A#er modeling each element with a numerical technique (MOM), this array is modeled with an equivalent

The composition and annealing characteristics of plasma deposited silicon nitride encapsulating films on ion implanted indium phosphide have been investigate d . X-ray photoelectron spectroscopy was employed to study the surface of InP substrates cleaned with organic solvents and HF or HIO3 solutions prior to encapsulation. The composition of silicon nitride films deposited with 13.56 MHz RF excitation was determined through Auger electron spectroscopy and infrared spectroscopy both before and after annealing. The hydrogen concentration decreased from 21 to 9% during annealing. InP substrates implanted with silicon at 100 keV to a dose of 5 • 1012 cm -2 and 150 keV to a dose of 3 • 1012 cm -2 had activations of approximately 60% after annealing at 700~ X-ray photoelectron spectroscopic measurements were performed at five depths through the silicon nitride/indium phosphide interface of an annealed and an unannealed sample. No chemical interaction between the film and the substrate was observed before or after annealing. However, a change in the composition of the interfacial native oxides upon annealing is suggested from differences between the oxygen peaks for the unannealed and annealed samples.There is considerable interest in the fabrication of devices and integrated circuits on indium phosphide (InP) substrates. This interest primarily derives from the large saturated drift velocity of electrons in InP and from the lower density of surface states at an insulator/InP interface than at an insulator/GaAs interface, which allows the fabrication of accumulation mode metal-insulator-semiconductor devices (1, 2). The thermal instability of InP at temperatures greater than 362~ (3) creates great difficulties for the development of a technology for doping InP through diffusion. Ion implantation, with its benefits of good control and reproducibility and its potential for allowing a planar and possibly self-aligned (4) fabrication technology, is an attractive alternative to diffusion or epitaxy. Since ion implantation disorders the crystal lattice and since the implanted species must be activated, it is necessary to anneal the substrate after implantation. The temperatures at which good implant activation can be achieved are sufficient to cause incongruent evaporation of the surface of the InP substrate (5). Surface protection can be achieved through the use of a thin encapsulating layer. Plasma deposited silicon nitride films are of particular interest as they are deposited at low temperatures (6). Among the properties of a good encapsulant are good adhesion to the substrate, resistance to cracking and blistering, and no chemical interaction with the substrate (5).The ability of a film to meet the adhesion requirements is related to the stress in the film and to the characteristics of the film-substrate interface which will be dependent on the InP cleaning procedure. We present here the results of a study of two procedures for cleaning InP substrates prior to encapsulation with plasma-deposited silicon nitride. The sil...

The role of GaAs surface cleaning and plasma reactor cleaning prior to deposition of silicon nitride films for encapsulated annealing has been investigated. X-ray photoelectron spectroscopy was employed to determine the surface characteristics of GaAs treated with HCl, HF, and NH4OH solutions preceded by a degreasing procedure. The HCl clean left the least amount of oxygen on the surface. Fluorine contamination resulting from the CF4 plasma used to clean the reactor was found to be located at the film-substrate interface by Auger electron spectroscopy with argon-ion sputtering. A modified deposition procedure was developed to eliminate the flourine contamination. Plasma deposition of silicon nitride encapsulating films was found to modify the I-V characteristics of Schottky diodes subsequently formed on the GaAs surface. The reverse current of the diodes was slightly reduced. Substrates implanted with Si at 100 keV and a dose of 5×1012/cm2 showed a peak electron concentration of 1.7×1017/cm3 at a depth of 0.1 μm with 60% activation after encapsulation and annealing at 800 °C for 7 min.