Mark V. Wadsworth

Monolithic CCD imagers in HgCdTe

Charge-coupled device (CCD) infrared detector arrays in 5 /spl mu/m cutoff HgCdTe have been demonstrated for low background applications. These fully monolithic 128 by 28 element CCD arrays incorporate time-delay-and-integrate (TDI) detection, serial readout multiplexing, charge-to-voltage conversion and buffer amplification in the HgCdTe detector chip. Operation of these devices at 77 K have produced average detectivity values exceeding 3/spl times/10/sup 13/ cm-Hz/sup 1/2//W for a background flux level of 6/spl times/10/sup 12/ photon/cm/sup 2/-sec in the 3.0 /spl mu/m to 5.5 /spl mu/m spectral band. Overall performance data indicates the monolithic HgCdTe CCD to be a promising alternative to present midwave infrared hybrid focal plane array technology. >

Field-extended field-effect transistors in 0.25-eV bandgap HgCdTe

A novel FET structure for use with 0.25-eV bandgap HgCdTe is described. The device, known as the field-extended field-effect transistor (FEFET), incorporates additional electrodes to control the surface electric field at the perimeter of the metallurgical diodes comprising the source and the drain of the transistor. Surrounding the metallurgical diodes with field-induced inversion regions improves the FEFET avalanche breakdown and subthreshold leakage characteristics as compared to standard MISFETs fabricated in HgCdTe. The FEFET is particularly attractive for switching applications or other uses requiring a high drain-to-source bias and a gate bias near the threshold potential. >

Monolithic CCD time-delay-and-integrate arrays in HgCdTe

Charge-coupled device (CCD) infrared detector arrays in 5 /spl mu/m cutoff HgCdTe have been demonstrated for low background applications. These fully monolithic CCD arrays incorporate time-delay-and-integrate (TDI) detection, serial readout multiplexing, charge-to-voltage conversion and buffer amplification in the HgCdTe detector chip. Performance data indicates the monolithic CCD to be a viable alternative to present hybrid focal plane array technology.<<ETX>>

Application of low-noise CID imagers in scientific instrumentation cameras

CIDTEC has developed a PC-based instrumentation camera incorporating a preamplifier per row CID imager and a microprocessor/LCA camera controller. The camera takes advantage of CID X-Y addressability to randomly read individual pixels and potentially overlapping pixel subsets in true nondestructive (NDRO) as well as destructive readout modes. Using an oxy- nitride fabricated CID and the NDRO readout technique, pixel full well and noise levels of approximately 1*106 and 40 electrons, respectively, were measured. Data taken from test structures indicates noise levels (which appear to be 1/f limited) can be reduced by a factor of two by eliminating the nitride under the preamplifier gate. Due to software programmability, versatile readout capabilities, wide dynamic range, and extended UV/IR capability, this camera appears to be ideally suited for use in spectroscopy and other scientific applications.

Selectable one-to-four-port, very high speed 512 x 512 charge-injection device

A high-speed 512 X 512 charge injection device with selectable one to four video ports has been developed, fabricated, and tested beyond the designed speed of operation. The imager has four independently controllable video ports allowing for all possible combinations. This is accomplished by having each port hard wired to one out of every four rows sequentially. Each port is selected via a multiplexer in the sequence desired. The horizontal scanner was designed to operate up to 30 MHz. The device was tested at the wafer level to 42 Mhz element rate per port. This element rate allows a maximum of 168 MHz element rate with four ports operating in parallel.