Abstract:
A light detector amplifier preferably fabricated as a monolithic integrated circuit has high speed of response (in the order of 1 microsecond) at low and high illumination levels, uses low quiescent power and supply voltage, and has an optional thyristor or power transistor output. A transistor preamplifier conducts in the quiescent state and reverse biases a photodiode. Upon illumination, current is diverted to the photodiode and a power amplifier is energized to produce an output which can also provide gating current for a thyristor output. Enhanced performance is obtained by the use of special components, and unique placement of components within the circuit. Voltage excursions are limited in the circuit at several points by current steering, pre-biasing and diode clamping techniques.
Abstract:
Undesired coupling of JFET or MESFET bucket-brigade stages through the epitaxial layer in a monolithic integrated bucketbrigade circuit is prevented by isolating adjacent stages by strips of thick oxide dielectric material such as SiO2. The dielectric strips are formed by selective oxidation to obtain local conversion of the n-type silicon epitaxial layer to SiO2. In a second embodiment, elongated spaced-apart mesas of the SiO2 are formed on the substrate prior to forming the patterned n-type silicon epitaxial layer. The storage capacitors of the bucketbrigade stages are MOS devices formed by metal layers overlapping the drain electrode regions of the JFETs or MESFETs diffused in the epitaxial layer with the dielectric material being a SiO2 layer therebetween.
Abstract:
A monolithic or discrete photodiode has a patterned region, preferably in the form of elongated strips or fingers, with a spacing less than the diffusion length to obtain low capacitance without loss of photo response. Enhanced efficiency is achieved by the use of surface skin regions and/or a buried layer to confine generated carriers, and by a structure that effects combination of the epitaxial layer-substrate photodiode with the finger photodiode. The low capacitance photodiode is sensitive to visible and infrared light and is useful in high speed circuit applications.
Abstract:
Compensation for undesired shifts in the D.C. voltage level of a signal being propagated through a charge-transfer delay line is provided by compensating stages spaced at regular intervals along the delay line. The compensating stages are preferably transistors of the same type as that used in the delay line and having their source (or drain) electrodes connected to appropriate nodes along the delay line and their gate electrodes supplied from a pulsed source of voltage having controllable voltage amplitude and pulse repetition rate. The drain (or source) electrodes are grounded for shifting the D.C. voltage level in a first polarity voltage direction and are open or connected to a D.C. voltage source for shifting in the opposite polarity voltage direction.
Abstract:
Undesired coupling of JFET or MESFET bucket-brigade stages through the epitaxial layer in a monolithic integrated bucketbrigade circuit is prevented by isolating adjacent stages by strips of thick oxide dielectric material such as SiO2. The dielectric strips are formed by selective oxidation to obtain local conversion of the n-type silicon epitaxial layer to SiO2. In a second embodiment, elongated spaced-apart mesas of the SiO2 are formed on the substrate prior to forming the patterned n-type silicon epitaxial layer. The storage capacitors of the bucketbrigade stages are MOS devices formed by metal layers overlapping the drain electrode regions of the JFETs or MESFETs diffused in the epitaxial layer with the dielectric material being a SiO2 layer therebetween.