Abstract: The tone or polarity of a patterned layer such as a photoresist mask on an integrated circuit or device substrate is reversed with substantially perfect alignment. A liquid planarizing layer is formed and hardened onto the patterned layer and underlying substrate, filling in spaces between pattern areas. The planarizing layer is then etched to a sufficient depth to expose the patterned layer. Finally, the patterned layer is dissolved away, leaving the reversed tone image which is constituted by the planarizing material in the spaces which were filled in. Modified embodiments enable large spaces between original pattern areas to be effectively reversed, and multi-level reversed tone images to be formed in which the reversed tone layers are thicker than the original layers.

Abstract: A masked ion beam lithography (MIBL) system and method is disclosed which is considerably more compact and economical than prior ion implantation devices. An H.sup.+ ion beam is extracted from a source in the form of an angularly expanding beam, and is transmitted through two lenses that sequentially accelerate the ions to energies in the range of 200-300 keV. The first lens focuses the beam so that it emerges from a crossover point with an amplified angular divergence at least three times the divergence of the initial beam, thereby considerably reducing the necessary column length. The second lens collimates the beam so that it can be directed onto a mask to expose resist on an underlying semiconductor substrate. A series of extraction electrodes are used to provide an initial point source beam with a desired angular expansion, and a specially designed sector magnet is positioned between the extraction mechanism and the first lens to remove particles heavier than H.sup.+ from the beam.

Abstract: A high speed photoconductive detector is disclosed which comprises two interdigital electrically conducting electrodes formed on a photoconductive layer. The device speed and sensitivity are improved by using a double-heterostructure configuration comprising an active layer formed on an isolation layer in turn formed on a supporting substrate. A passivation layer is formed on the active layer. This configuration confines the generated carriers to the active layer. Consequently, current will be induced under optical illumination due to photo-carrier generation. This interdigitated geometry allows for a large device cross-section and small carrier transit distance.

Abstract: A high speed photoconductive detector is disclosed which comprises two interdigital electrically conducting electrodes formed on a photoconductive layer. The device speed and sensitivity are improved by using a double-heterostructure configuration comprising an active layer formed on an isolation layer in turn formed on a supporting substrate. A passivation layer is formed on the active layer. This configuration confines the generated carriers to the active layer. Consequently, current will be induced under optical illumination due to photo-carrier generation. This interdigitated geometry allows for a large device cross-section and small carrier transit distance.

Abstract: A GaAs FET structure with a high electric field region, or active region, contacted by source, gate and drain electrodes is provided which can be used for high speed optical detection or for microwave oscillator optical injection locking. The device provides for efficient coupling of incident optical radiation into the active region, employing confinement and waveguiding regions lying in the plane of the device and adapted to guide incident optical radiation to the active region. GaAs photoconductors are also provided by eliminating the gate electrode.