An improved photodetector array in which each element of the array is provided with an integral pair of MOSFET switches, so that scanning of the m by n array can be accomplished with only m + n conductors leading from the array to scanning circuitry: an integral discrete capacitor is also included to augment the capacitance inherent in the PN junction of each diode element.
An opto-electronic device configured as a photodetector has a capacitor and/or resistor monolithically formed on a surface of the photodetector. The capacitor capacitively couples the AC ground of the photodetector to the bias terminal of the photodetector. The on chip capacitor design eliminates the inductance of external circuit traces between the power supply and an external capacitor. The resistor forces the AC return current of the photodetector through the AC ground in preference to the typical (DC bias terminal) path. Combinations of capacitors and resistors are particularly effective in reducing crosstalk among adjacent detectors in arrays.
A semiconductor integrated circuit is described which includes an array of electronic devices and a plurality of electronic access devices. The access devices consist of sets of MOSFETs which may be turned on by the joint action of X and Y address lines to permit individual and isolated electrical connection between selected electronic devices in the array and peripheral on or off-chip sensing circuits. This permits continuous readout to be established and maintained for the selected devices without interference with the other devices in the array and without a requirement to readout any but the selected devices. One important embodiment of the present invention is one in which the electronic devices are visible or infrared radiation detectors. In order to provide minimum dead space between the array detectors, the array and access devices may be disposed on opposite surfaces of the semiconductor body.
An opto-electronic device configured as a photodetector has a capacitor and/or resistor monolithically formed on a surface of the photodetector. The capacitor capacitively couples the AC ground of the photodetector to the bias terminal of the photodetector. The on chip capacitor design eliminates the inductance of external circuit traces between the power supply and an external capacitor. The resistor forces the AC return current of the photodetector through the AC ground in preference to the typical (DC bias terminal) path. Combinations of capacitors and resistors are particularly effective in reducing crosstalk among adjacent detectors in arrays.
A P-channel MOS double gated transistor is provided with an electrical shield element located between the drain and the second gate. The shield is electrically connected to the first gate and is dc biased by the first gate control voltage at FIRST GATE SELECT. The presence of the first gate control voltage causes all the shield capacitances to charge and causes a depletion region between the shield and the drain. Prior to SECOND GATE SELECT, the electrical transient effects of activating the shield with a dc bias have expired. SECOND GATE SELECT introduces new transients (noise current), noteable charging of the capacitance between the drain and the second gate and formation of the final section of depletion region proximate the second gate completing the P channel. This capacitance is drastically reduced by the intervening shield, and the depletion transient is minimized by the priming depletion region established by the shield voltage.
An InGaAs semiconductor device implemented on a semiconductor substrate having a first major surface on which active semiconductor devices are to be formed, and a second major surface. An etch stop layer is provided on the first major surface. A layer of semiconductor material is provided on the etch stop layer and portions of the substrate are selectively removed to provide a pattern of apertures in the layer extending to the etch stop layer. Dopant species are provided through the second major surface to form active regions in the layer of semiconductor material. The resulting structure permits the integration of optoelectronic devices with photoelectronic devices on the same substrate.