Abstract: Leak detector using infrared for identifying the presence and concentration of a selected gas. For detection, radiation from an infrared emitter penetrates the sample, which is analyzed spectrally, and results in a wave length-specific signal being generated at the output. By controlling the optical filter, the radiation is controlled at a selected wavelength, to ensure coverage of all selected compounds. For refrigerants, the selected wavelength can be between approximately 8 to approximately 10 microns. This wavelength obscures other signals, thus minimizing false alarms. The leak detector has a faster time with no adverse impacts on the accuracy of the compound being detected. To further minimize false alarms and to ensure that the emitter does not come in contact with the gas, an additional filter can be used. For refrigerant compounds, the filter can block out signals below approximately 6 microns. For detecting refrigerants, two filters can be used.

Abstract: A leak detector using an infrared emitter and pyroelectric sensor to form an instrument for identifying the presence and concentration of a selected material type gas compound, such as a refrigerant gas compound within a given sample, such as a sample of ambient air. For the detection, a radiation flux coming from an infrared emitter penetrates the sample, which is analyzed spectrally, and results in a wave length-specific signal being generated at the output of the detector. By controlling the type of optical filter, the radiation energy is controlled at a selected wavelength, to ensure coverage of all selected compounds. For refrigerants, the selected wavelength can be between approximately 8 to approximately 10 microns in the wavelength range. This selected wavelength obscures other signals, thus minimizing false alarms. By not chopping or pulsing the emitter, the leak detector has a faster response time with no adverse impacts on the accuracy of the compound material being detected.

Abstract: A two-step analog-to-digital converter and BiCMOS fabrication method. The fabrication method provides pseudosubstrate isolation of digital CMOS devices from the analog devices. The converter uses NPN current switching in a flash analog-to-digital converter and in a digital-to-analog converter for low noise operation. CMOS digital error correction and BiCMOS output drivers provide high packing density plus large output load handling. Timing control aggregates switching events and puts them into intervals when noise sensitive operations are inactive. The fabrication method uses a thin epitaxial layer with limited thermal processing to provide NPN and PNP devices with large breakdown and Early voltages. Laser trimmed resistors provide small long term drift due to dopant stabilization in underlying BPSG and low hydrogen nitride passivation.

Abstract: A bipolar transistor having an improved collector structure includes a buried region of the same conductivity type as the collector region spaced from the base region and having a laterally graded impurity concentration with the lowest below the center of the emitter .region. An integrated circuit may include transistors having the buried collector region of the diminishing lateral impurity concentration below the center of its emitter as well as having transistors with a uniform lateral impurity concentration below the total lateral extent of the emitter. A method of achieving the unique collector region includes forming at least a first collector region of a first conductivity type as two lateral portions of substantially uniform lateral impurity concentration with a space therebetween in a substrate of a second conductivity type and heating to form the buried collector structure of diminishing lateral impurity concentration.

Abstract: A bipolar transistor having an improved collector structure includes a buried region of the same conductivity type as the collector region spaced from the base region and having a laterally graded impurity concentration with the lowest below the center of the emitter region. An integrated circuit may include transistors having the buried collector region of the diminishing lateral impurity concentration below the center of its emitter as well as having transistors with a uniform lateral impurity concentration below the total lateral extent of the emitter. A method of achieving the unique collector region includes forming at least a first collector region of a first conductivity type as two lateral portions of substantially uniform lateral impurity concentration with a space therebetween in a substrate of a second conductivity type and heating to form the buried collector struture of diminishing lateral impurity concentration.

Abstract: An SOI/SOS thin film MOS mesa architecture has its body/channel region extended beyond the source and drain regions and the impurity concentration is increased at a selected portion (e.g. an end portion) of the extended body region, so as to provide both a body tie access location which enables the body/channel region to be terminated to a prescribed bias voltage (e.g. Vss), and a channel stop region that is effective to functionally interrupt a current leakage path or `parasitic` N-channel that may be induced along sidewall surface of the P-type material of the body/channel region. In another embodiment, ionizing radiation-induced inversion of the sidewalls of the P-type body/channel region is prevented by an asymmetric sidewall channel stop structure formed in opposite end portions of the source region.