Abstract: Optoelectronic devices (16) are formed on a first surface (12) of a gallium arsenide substrate (10) using selective ion implantation. Signal processing devices may be formed on a second, opposite surface (14) of the substrate (10) using selective ion implantation (38) and/or selective epitaxy (22,24),(40). Vertical interconnects (34,46) are formed between the first and second surfaces (12,14). Alternatively, a gallium arsenide buffer layer (54) may be grown on the first surface (12) of the substrate (10), and the signal processing devices formed on the buffer layer (54) using selective ion implantation (58,60,62) and/or selective epitaxy (76,78,80,82). Dielectric (50) and/or conductive metal (52) layers may be formed on selected areas of the first surface (12), and the buffer layer (54) grown from exposed areas (56) of the first surface (12) over the dielectric (50) and/or metal (52) layers using lateral epitaxial overgrowth organometallic chemical vapor deposition.

Abstract: A process for fabricating varactor diodes using ion implantation techniques is described herein. Three successive implanations of N-type ions into a GaAs semi-insulating substrate provide a deep N.sup.+ type conductivity layer about 2-3 microns below the front major surface with concentration of at least 2.times.10.sup.18 ions/cm.sup.3. A fourth implantation of N type ions forms an N type conductivity layer over the N.sup.+ layer. An implanation of P type ions forms the P type conductivity layer over the N type conducitivity layer. A single rapid thermal anneal is performed on the substrate to remove damage to the crystal structure and to electrically activate the implants. The basic doped layered semiconductor structure is thereby produced using ion implantation. This ion implantation process provides a method for fabricating monolithic diode devices reliably and in mass quantities, which can be integrated with other monolithic devices.

Abstract: There is herein described a process for fabricating GaAs FETs with an ion implanted channel layer wherein an ion implanted substrate is capless annealed under an arsine overpressure, and a relatively shallow portion of the outer surface of the substrate in the active layer is removed for the deposition of a gate metallic electrode.

Abstract: Sound waves are utilized to apply torque to a body in an enclosure of square cross section, by driving two transducers located on perpendicular walls of an enclosure, at the same frequency but at a predetermined phase difference such as 90.degree.. The torque is a first order effect, so that large and controlled rotational speeds can be obtained.