Abstract:
A method comprising the steps of depositing a first and second polysilicon layer, separated by an oxide layer; selectively etching the second polysilicon layer to form first gate regions; forming first substrate regions in the substrate and laterally in relation to the first gate regions; selectively etching the first polysilicon layer to form second gate regions of a length greater than the first gate regions; and forming in the substrate, laterally in relation to the second gate regions and partially overlapping the first substrate regions, second substrate regions of a higher doping level than the first substrate regions.
Abstract:
The circuit comprises a tank capacitance and a charge circuit supplied with the same voltage as the bridge and comprising an inductance and a control transistor. There is also provided a control circuit, which comprises an oscillator controlling the periodic switching of control transistor and a comparator which controls the momentary clamping of control transistor in the condition wherein the charge circuit is interrupted when the difference between the voltage across capacitance and the power supply voltage exceeds a present maximum value and the unclamping of the same transistor when such difference falls below a preset minimum value. A further comparator similarly clamps control transistor if there is an excess current in the transistor itself.
Abstract:
A method of measuring under running conditions operation parameters of an interface circuit and a telephone subscriber line connected to it, said interface circuit comprising a first integrated circuit operating on a high voltage with outputs connected to the line and second outputs on which transverse and longitudinal current values of the line are respectively present in normal operation, and a second integrated circuit operating on a low voltage between the first circuit and a telephone exchange, comprises the steps of: switching the outputs across an impedance of a predetermined value, and measuring through the first circuit the values of the currents present on the second outputs; switching said outputs back to across the line leads, and measuring through the first circuit the values of the transverse and longitudinal line current values; performing, for each measurement through the second circuit, a digital encoding of the measured values and transmitting such encoded values to the telephone exchange.
Abstract:
A circuit comprising a transistor which, when supply is turned off, locks the output of the audio amplifier to the supply line, the potential of which is reduced gradually by a filter capacitor, so that the output voltage follows the supply voltage with the same slope, and is so controlled by the filter capacitor, thus eliminating undesired noise ("popping") at the output caused by electric transients in the audio amplifier.
Abstract:
A device for controlling the linearity of a horizontal deflection stage comprising a deflection yoke supplied with a yoke current controlled by a switch and series-connected to a capacitor for varying the yoke voltage according to the phase of the yoke current; the device comprising a circuit for detecting and generating a real signal proportional to the yoke current, a ramp generator for generating an ideal ramp signal having rising portions defining a given S-shaped wave:form, and an error amplifier for receiving the real and ideal ramp signals and generating an error signal for driving a power transistor having its emitter and collector terminals connected parallel to the capacitor for modifying the voltage in the capacitor so that the yoke current assumes the required waveform.
Abstract:
A packaging structure is disclosed for a semiconductor device, having a body configured to include at least one part provided with contact terminals and shaped to form a connector member for direct coupling to a standard connector member from an external circuit. A connector assembly is also disclosed which is fully sealed from moisture and comprises the packaging structure.
Abstract:
Highly reliable direct contacts may be formed by defining a direct contact area within a larger area purposely implanted and diffused for ensuring electrical continuity in the semiconductor. Patterning may define the contacting polysilicon within an implanted direct contact area so that the definition edges thereof fall on a gate oxide layer thus preventing an etching of the semiconductor during the unavoidable over-etching that concludes the polysilicon patterning step. Preferably, a pre-definition of the direct contact area is performed through a first, deposited layer of polysilicon, which effectively protects a gate oxide layer during a HF wash prior to depositing a second, contacting layer of polysilicon of adequate thickness.
Abstract:
A method for producing electrically erasable and programmable read-only memory cells with a single polysilicon level, including the use of a sacrificial layer of silicon oxide to produce a high-thickness silicon oxide layer on the active area. The active area of the cell is protected from heavy source and drain implantation in order to improve reliability.
Abstract:
A device for heating chemical tanks includes at least one heat exchanger coil immersed inside a chemical tank. An inert gas, such as nitrogen, is heated and made to flow through the coil to heat a solution in the chemical tank to the desired temperature, which is sensed by a sensor. If microfractures form in the heat exchanger coil, the inert gas simply bubbles out of the solution and does not adversely impact the purity of the solution. In addition, the bubbling of the gas indicates the presence of a microfracture. A second heating coil is provided, and also provides heated inert fluid for heating the solution in the tank. The fluid flow through the first coil is controlled linearly to maintain the temperature at the desired temperature. The fluid flow through the second coil is controlled impulsively to quickly return the solution to the desired temperature after a temperature transient occurs, such as after a relatively cool object is immersed into the solution.
Abstract:
An integrated protective structure provides protection from electrostatic discharges of structures to an integrated circuit functionally connected to a certain external pin. The protective structure is formed in a single epitaxial tub and includes a triggering Zener diode and a vertical bipolar transistor. The collector region of the vertical bipolar transistor is connected to the pin and constitutes also one of the two terminal regions of the triggering Zener. Around the emitter region and separated therefrom by the smallest distance feasible, is an annular region, having a heavier doping than the base region of the transistor formed with the purpose of intercepting the avalanche current of the Zener junction and distributing it in a uniform manner into the base region of the vertical transistor as well as acting as a shield for eventual electrons moving from the emitter region toward the breakdown junction. Optionally, a further emitter region, may be formed in front of the collector/cathode region and connected to the annular region in order to create a lateral bipolar transistor which triggers-on during an electrostatic discharge; thus, reducing the ohmic drop through the protective structure and the breakdown voltage.