Abstract: Method and apparatus for delivery of chemical reagents to a subterranean body of soil and groundwater to destroy or enhance mobility of organic compounds using a riser insertable in a borehole having spaced permeable sections separated by a non-permeable section and wherein the reagents are introduced from a source by a pressurization apparatus.

Abstract: A plurality of microwave semiconductor devices is provided by plating a thin conductive layer on a surface of a wafer of semiconductor material, masking selected portions of the thin conductive layer, and plating unmasked portions of the thin conductive layer to form a thicker, apertured support layer with the apertures in the support layer providing a thin contact. After forming the thicker, apertured support layer, substantial portions of the semiconductor material are removed to form the semiconductor devices as a plurality of mesa shaped diodes, with each one of the semiconductor mesa shaped diodes being formed on a corresponding one of the thin contacts, and with the plurality of mesa shaped diodes being mutually supported by the support layer and integrally formed thin contacts. Each contact and the support are selectively etched to pattern portions of the support and thin contacts into a frame.

Abstract: A plurality of microwave semiconductor devices is provided by plating a thin conductive layer on a surface of a wafer of semiconductor material, masking selected portions of the thin conductive layer, and plating unmasked portions of the thin conductive layer to form a thicker, apertured support layer with the apertures in the support layer providing a thin contact. After forming the thicker, apertured support layer, substantial portions of the semiconductor material are removed to form the semiconductor devices as a plurality of mesa shaped diodes, with each one of the semiconductor mesa shaped diodes being formed on a corresponding one of the thin contacts, and with the plurality of mesa shaped diodes being mutually supported by the support layer and integrally formed thin contacts. Each contact and the support are selectively etched to pattern portions of the support and thin contacts into a frame.

Abstract: A method for producing doped gallium arsenide semiconductor layers for semiconductor devices wherein a predetermined flow of a reactive substance is directed over a material having a dopant and a relatively low vapor pressure. The reactive substance chemically reacts with the material to produce a corresponding flow of a doping vapor. The doped gallium arsenide semiconductor layer is deposited on a gallium arsenide substrate by vapor phase epitaxy from material including the doping vapor. With such method, accurate control of the magnitude of the dopant is obtained by control of the reactive substance, the doping material being supplied by a non-volatile source.

Abstract: A modified Read-type diode having an extremely thin doping spike and with the electric field in the drift region terminated before the buffer zone. The buffer zone and a drift region are first grown upon a doped semiconductor substrate using epitaxial vapor deposition growth techniques employing a furnace tube within a multiple temperature zone reaction furnace. The doping spike is produced by injecting under pressure a fixed predetermined volume of dopant into the furnace tube. An avalanche region is grown over the doping spike and a Schottky barrier contact or semiconducting material of the opposite conductivity type grown over the avalanche region. Avalanche regions having a length less than 15% of the total active length of the device and doping spikes having a width of 500 A or less are disclosed in a high-efficiency device.