Walter F. Kosonocky

160 × 244 Element PtSi Schottky-barrier IR-CCD image sensor

A 160 × 244 element IR-CCD image sensor was developed with PtSi Schottky-barrier detectors (SBDs) for thermal imaging in the 3.0-5.0-µm IR band. This imager has 80 × 40 µm2pixels, a fill factor of 39 percent, and a chip size of 584 × 464 mil2. It produces excellent quality thermal imaging with noise-equivalent temperature (NEΔT) of less than 0.1 K for operation at 30 frames/s with standard-TV-interlace f/2.3 optics, and one-point offset-type uniformity corrector. This paper describes the design, construction, and performance of 160 × 244 element IR-CCD imager and the characteristics of the PtSi Schottky-barrier detector elements.

Saturation of Absorption and Fluorescence in Solutions of Phthalocyanines

Lifetimes of the excited states of phthalocyanines are studied by the irradiation of solutions with a Q‐switched ruby laser. By detailed measurements of the saturation of fluorescence and absorption with increasing‐pulse laser power, the radiative and the nonradiative lifetimes of S1 as well as the time constants for the S1 → T1 and T1 → S0 transitions are determined. The transition between the ground state and the first excited singlet state in the metal‐free as well as the metallophthalocyanine saturates at laser pulse flux power densities of 0.1 to 0.15 MW/cm2. A complete transition of the molecular system from a ground state, S0, into a triplet state, T1, is observed in the case of the metal‐free phthalocyanine H2Pc. The triplet state has a relaxation time to the ground state of 1.0 μsec at 300°K and 150 μsec at 77°K. The absence of fluorescence in VOPc and CuPc implies that a third state also is involved in the saturation of the absorption of the metallophthalocyanines. In these solutions, the satura...

Design and performance of two-phase charge-coupled devices with overlapping polysilicon and aluminum gates

The design, fabrication, operation, performance and analysis of two-phase surface channel, CCD shift registers built using a polysilicon overlapped by aluminum gate technology will be presented. The devices studied consist of previously described 64 and 128-stage shift registers with 1.2 mil center-to-center spacing and a new 500 stage device with 0.8 mil center-to-center spacing, including various channel widths of 5.0, 1.0 and 0.5 mil. Devices were fabricated on a variety of different substrates including

Parametric Phase-Locked OscillatorߞCharacteristics and Applications to Digital Systems

The ability of the Parametric Phase-Locked Oscillator (PLO) to detect, amplify, and store binary digital signals, in the form of two distinct phases of a carrier, makes it possible to use the device as the sole component in a digital computer system. The variable-capacitance version of the device operates readily at kilomegacycle frequencies, thus forming the basis of a digital computer at a kilomegapulse clock rate. In the present paper the results of an investigation of the behavior and possible applications of the variable-capacitance PLO are presented. The investigation was supported by experimental work with lumped-component variable-capacitance PLOs at 5 mc, and microwave variable-capacitance PLOs at 4 kmc. The steady-state behavior of the device is described; variations of the output voltage with pump voltage, loading, tuning and frequency variations are presented in the form of characteristic curves. Results indicate that the device is rather insensitive to reasonable changes in operating conditions and parameter values. The transient behavior of the PLO shows that the device can be switched in a number of different ways. Five such modes of operation are discussed; these are phase initiation, forced switching, burst generation, tri-stable operation and unconditional switching. Each of these modes has particular advantages for various applications. Switching times of the order of 3 to 10 cycles of the signal frequency are readily obtainable. The various modes of operation of the device suggest a number of applications both in logic and in memory.

Blooming control and dynamic range in charge-coupled imagers

In practical applications charge-coupled imagers (CCIs) should be immune to picture degradation due to excessive local optical overloads while maintaining large dynamic range. Our analysis shows that a 500 × 500 CCI will have a sensitivity approaching the I-SIT (within a factor of 10) and an intra scene dynamic range of approximately 1000:1 for a scene contrast of 0.2. However, to maintain useful operation under excessive local overloads (up to 105), some type of blooming control is required which is capable of removing the excess charge from the photosensitive area. Two general categories of blooming ccntrol structures for charge-coupled area sensors with illuminated registers will be described. Operation, design tradeoffs, and experimental data will be presented for: (a) blooming control structures which are process-compatibile with single-metal 3-phase CCIs, and (b) for blooming control structures more suitable for sealed channel, silicon gate, 2-phase CCIs. Blooming control methods will also be described for sensors having separate photodiodes with nonilluminated registers.

Schottky-Barrier Infrared Charge-Coupled Device Focal Plane Arrays

Recent development of high-performance Pd2Si and PtSi Schottky-barrier IR-CCD image sensors make these monolithic focal plane arrays attractive for many SWIR and thermal imaging applications. PtSi Schottky-barrier detectors operated at 80K have quantum efficiency of several percent in the 3 to 5 μm spectral range and cut-off wavelength of about 6.0 μm. Pd2Si Schottky-barrier detectors operated between 120 and 140K have cut-off wavelength of 3.6 μm and quantum efficiency in the range of 1.0 to 8.0% in the SWIR band. High-quality thermal imaging was achieved with a 64x128-element PtSi Schottky-barrier IR-CCD imager in a TV compatible IR camera operated with 60 frames per second. This paper reviews the Schottky-barrier IR-CCD technology developed at RCA. A model for photoyield of Schottky-barrier detectors (SBDs) is reviewed and compared with experimen-tal data. The architecture and design trade-offs of the SBD IR-CCD imagers are discussed. Also included is a discussion of the quantum efficiency requirements for staring thermal imagers and the performance achievable with the Schottky-barrier IR-CCD arrays.

(Invited) “High-Performance Schottky-Barrier IR-CCD Image Sensors”

High-performance PtSi and Pd2Si Schottky-barrier IR-CCD image sensors were developed with 32×63 and 64×128 elements. PtSi Schottky-barrier detectors (SBDs) operated at 80 K have quantum efficiency of several percent in the 3 to 5 µm spectral range and cut-off wavelength of about 6.0 µm. Pd2Si SBDs operated between 120 and 140 K have cut-off wavelength of 3.6 µm and quantum efficiency in the range of 1.0 to 8.0% in the 1.0 to 2.5 µm band. High quality thermal imaging has been demonstrated with a 64×128-element PtSi Schottky-barrier IR-CCD imager in a TV compatible IR camera operated with 60 frames per second. Also SWIR reflective infrared imaging of very good quality was achieved with the Pd2Si Schottky-barrier IR-CCD image sensor.

Experimental measurement of noise in charge-coupled devices

Various workers have predicted that the CCD should be a low-noise device. This paper will discuss measurements of noise in 32, 64 and 128 bit 2-phase silicon/aluminum gate CCDs which tend to confirm these low noise predictions. The various noise sources expected in CCDs (i.e.: Shot noise of signal and background charge, incomplete transfer noise, fast interface state noise, and output amplifier channel and reset noise) will be briefly discussed along with the spectral density anticipated for uncorrelated and correlated noise sources.

Visible and infrared solid-state image sensors

This paper reviews the progress, major issues, and trends in the development of solid-state visible and infrared image sensors. The most common photodetector readout structure and imager architectures are discussed. This presentation also includes a brief review of recently reported visible and infrared image sensing arrays.

Charge-coupled devices for computer memories

The charge-coupled device (CCD) is an analog shift register which is based upon MOS (metal-oxide semiconductor) technology and is capable of large scale integration. As an analog device it offers exciting and unique capabilities as an image sensor and in a variety of signal processing and filtering applications.