Stmicroelectronics Gmbh

Sgs-Thomson Microelectronics Limited

Stmicroelectronics S.a.

Mehdi Zamanian

Tsiu Chiu Chan

David C McClure

Fu-Tai Liou

Rong Yin

Ravi Sundaresan

James Leon Worley

Pervez Hassan Sagarwala

Mark A Lysinger

Philippe Roche

François Jacquet

William A Bishop

A memory circuit has a high voltage and low voltage supply nodes. One of a first and second sets of voltages is selectively applied to the supply nodes of the memory circuit in dependence upon memory operational mode. If in active read/write mode, then the first set of voltages is selectively applied. Conversely, if in standby no-read/no-write mode, then the second set of voltages is selectively applied. A low voltage in the second set of voltages is greater than a low voltage in the first set of voltages by a selected one of a plurality of low offset voltages, and a high voltage in the second set of voltages is less than a high voltage in the first set of voltages by a selected one of a plurality of high offset voltages. The offset voltages are provided by diode-based circuits that are selectively active. Selective activation is provided by either selectably blowable fuse elements or selectively activated switching elements.

Programmable SRAM source bias scheme for use with switchable SRAM power supply sets of voltages

A regulator circuit and method are disclosed for a system. The regulator circuit may include a compare circuit for comparing a first supply voltage to a predetermined voltage level and generating an enable signal based upon the comparison. A selectively enabled voltage regulator is adapted to make available a predetermined current level at a regulated voltage when enabled by the compare circuit. When disabled, the voltage regulator circuit is prohibited from providing current. The voltage regulator may include an output transistor that is normally biased in a saturation mode of operation and is deactivated by the enable signal. By controlling the output transistor based upon the output of the compare circuit, the need for a relatively large transistor for connecting to the first supply voltage is eliminated.

Regulator circuitry and method

A method and circuit are disclosed for enabling an oscillator circuit to oscillate a predetermined period of time following completion of a power-up operation. The circuit may include a counter having a control for receiving a control signal from a system power-on-reset circuit, and a clock input. A ring oscillator has an output coupled to the clock input of the counter.

Startup circuit and method for starting an oscillator after power-off

A method of fabricating an integrated circuit having an n-channel and a p-channel transistor is provided. The method includes forming LDD regions for the n-channel transistors self-aligned to the gate electrodes. A first oxide is then formed over the structure and the n-type silicon regions are implanting with a p&plus; type dopant through the first oxide to form the source and drain regions of the p-channel transistor. A second oxide is formed over structure. The two oxide layers are then etched to provide sidewall spacers, having an inner portion formed from the first oxide and an outer portion formed from the second oxide. The p-type silicon regions are implanted with an n&plus; type dopant to form the low resistivity regions of the n-channel transistor. The p&plus; implants in the source and drain of the p-channel transistor typically outdiffuse toward the gates during further thermal processing of the device. The resulting integrated circuit has an LDD n-channel transistor and a p-channel transistor without an LDD region.

CMOS integrated circuit device with LDD n-channel transistor and non-LDD p-channel transistor

A frequency test circuit ( ) includes a built-in self test (BIST) circuit ( ) which provides for testing of a frequency generating circuit such as an oscillator circuit ( ). The test circuit ( ) includes circuit stages ( ) which help produce a reference signal ( ) which has substantially the same frequency as that produced by the oscillator circuit ( ) when it is operational. Since the low current oscillator circuit ( ) can fail at any one of the divider or level shifting stages ( ), the test circuit ( ) can determine if the reference signal and the output signal of the oscillator have substantially the same frequency and produce a test condition signal indicative of either a pass or failed test at test port ( ).

Built-in frequency test circuit for testing the frequency of the output of a frequency generating circuit

A method is disclosed for a memory cell for a static random access memory. The memory cell includes a pair of cross-coupled CMOS logic inverters that are connected together to form a latch, and a pair of p-channel transmission gate transistors that are connected to the logic inverters for selectively providing access to the latch. The layout of the memory cell includes a rectangular active area in which the p-channel transistors of the memory cell are located. The rectangular active area abuts a similar active area of an adjacent memory cell along a row of memory cells so as to form a single rectangular active area for the p-channel memory cell transistors. The rectangular active area reduces the occurrence of fabrication-related phenomena that adversely effect the performance of the memory cell.

Method of fabricating a memory cell for a static random access memory

A circuit and method is disclosed for a memory cell for a static random access memory. The memory cell includes a pair of cross-coupled CMOS logic inverters that are connected together to form a latch, and a pair of p-channel transmission gate transistors that are connected to the logic inverters for selectively providing access to the latch. The layout of the memory cell includes a rectangular active area in which the p-channel transistors of the memory cell are located. The rectangular active area abuts a similar active area of an adjacent memory cell along a row of memory cells so as to form a single rectangular active area for the p-channel memory cell transistors. The rectangular active area reduces the occurrence of fabrication-related phenomena that adversely effect the performance of the memory cell.

Circuit and method of fabricating a memory cell for a static random access memory

Method of fabricating a CMOS integrated circuit device with LDD N-channel transistor and non-LDD P-channel transistor

A radiation hardened memory device having static random access memory cells includes active gate isolation structures placed in series with oxide isolation regions between the active regions of a memory cell array. The active gate isolation structure includes a gate oxide and polycrystalline silicon gate layer electrically coupled to a supply terminal resulting in an active gate isolation structure that prevents a conductive channel extending from adjacent active regions from forming. The gate oxide of the active gate isolation structures is relatively thin compared to the conventional oxide isolation regions and thus, will be less susceptible to any adverse influence from trapped charges caused by radiation exposure.

Radiation hardened semiconductor memory

A method is provided of forming a small geometry via or contact of a semiconductor integrated circuit, and an integrated circuit formed according to the same, is disclosed. According to a first disclosed embodiment, an opening is formed partially through an insulating layer overlying a conductive region. Sidewall spacers are formed along the sidewalls of the opening. The remaining insulating layer is etched to expose the underlying conductive region. The contact dimension of the opening is smaller than the opening which can be printed from modern photolithography techniques. According to an alternate embodiment, the opening in the insulating layer expose the underlying conductive region. A polysilicon layer is formed over the insulating layer and in the opening. The polysilicon is oxidized to form a thick oxide in the opening and is etched back to form oxidized polysilicon sidewall spacers which decrease the contact dimension of the opening. According to a further alternate embodiment, an etch stop layer is formed between the insulating layer and conductive region and an opening is formed in the insulating layer exposing the etch stop layer. A sidewall spacer film is formed over the insulating layer and the etch stop layer, both layers having a similar etch rate for a given etchant. The etch stop and spacer layers are etched in the opening to expose the underlying conductive layer thereby forming a contiguous sidewall spacer and etch stop layer on the sides of and under the insulating layer, thereby decreasing the contact dimension of the opening.

Method of forming submicron contacts and vias in an integrated circuit

The invention may be incorporated into a method for forming a vertically oriented semiconductor device structure, and the semiconductor structure formed thereby, by forming a first transistor over a portion of a substrate wherein the first transistor has a gate electrode and a source and drain regions. First and second interconnect regions are formed over a portion of the gate electrode and a portion of the source and drain regions of the first transistor, respectively. A source and drain region of a second transistor is formed over the second interconnect. A Vcc conductive layer is formed over a portion of the source and drain region of the second transistor which is formed over the second interconnect.

Method of forming a portion of a memory cell

A frequency test circuit (200) includes a built-in self test (BIST) circuit (212) which provides for testing of a frequency generating circuit such as an oscillator circuit (100). The test circuit (200) includes circuit stages (202-208) which help produce a reference signal (210) which has substantially the same frequency as that produced by the oscillator circuit (100) when it is operational. Since the low current oscillator circuit (100) can fail at any one of the divider or level shifting stages (106-112), the test circuit (200) can determine if the reference signal and the output signal of the oscillator have substantially the same frequency and produce a test condition signal indicative of either a pass or failed test at test port (214).

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Carrollton, TX, United States of America

Mehdi Zamanian