Hewlett-packard Company

Menlo Industries, Inc.

Hewlett-packard Corporation

Chung-Yi Su

Ghulam Hasnain

James N Hollenhorst

Sanehiko Kakihana

William J Anklam

Domingo A Figueredo

Michael R Tan

Michael R Ty Tan

A mesa-structure avalanche photodiode in which a buffer region in the surface of the mesa structure effectively eliminates the sharply-angled, heavily doped part of the cap layer that existed adjacent the lightly-doped n-type multiplication layer and p-type guard ring before the buffer region was formed. This reduces electric field strength at the ends of the planar epitaxial P-N junction and prevents edge breakdown in this junction. The lateral extent of the guard ring is defined by a window formed in a masking layer prior to regrowth of the guard ring. This guard ring structure eliminates the need to perform additional processing steps to define the lateral extent of the guard ring and passivate the periphery of the guard ring.

Mesa-structure avalanche photodiode having a buried epitaxial junction

A SAM avalanche photodiode formed with an epitaxially regrown guard ring and a planar P-N junction defined between a cap layer and a multiplication layer. The multiplication layer is part of a multi-layer semiconductor platform having a conductivity opposite to the conductivity type of the cap layer, including a light absorption layer, a substrate and an intermediate layer. A second embodiment of the present invention is disclosed including a SAM avalanche photodiode having a guard ring with a variable distribution of impurity dopant concentrations. In addition, a third embodiment of the present invention is disclosed in which a narrow band gap layer completely covers the cap layer and a non-alloy metal contact is formed to completely cover the narrow band gap layer, forming a mirror junction. In this embodiment, incident light is shined through the substrate and reflected from the mirror junction, enhancing the absorption efficiency.

Method of making avalanche photodiodes with epitaxially-regrown guard

Avalanche photodiode with epitaxially regrown guard rings

A tunnel diode is disclosed having a highly P-doped layer of indium gallium arsenide formed on a highly N-doped layer of indium gallium arsenide which is supported on a semi-insulating substrate of indium phosphide. In an alternative embodiment, a tunnel diode is disclosed which has a highly P-doped layer of indium gallium arsenide formed on a highly N-doped layer of indium gallium arsenide which is supported on an N-doped substrate.

Tunnel diode detector for microwave frequency applications

A Monolithic Sampler is disclosed. The present invention overcomes the problem of inadequately low sampling rates that results from circuit designs or component limitations that constrain the bandwidths of previous instruments. The sampler includes five circuit stages: a local oscillator section that may be used to drive the system, a shock wave generator that produces high frequency edge-sharpened pulses, a reflection damping clamping section, a delay section, and a sampler section regulated by the stream of shock waves which produces an IF output. The local oscillator or a pulse generator (not shown) produces an input that propagates down a nonlinear transmission line. Once this input reaches the shock wave generator section, it encounters a series of hyperabrupt diodes which are employed as voltage dependent capacitors called varactors. These varactors deform the input pulses and generate a stream of spike-shaped waveforms known as shock waves. The shock waves successively energize sampling diodes in the sampling section of the circuit. When these diodes are energized, they open pathways from an RF input to sampling capacitors which charge up with small representative bits of current from the input. A sample or snapshot of the input is drawn from these capacitors through an IF output coupling network. The clamping and delay sections of the sampler minimize spurious ringing throughout the circuit and manage the timing of the oscillation of these reflections. The entire sampler is monolithically integrated on a single substrate using conventional semiconductor fabrication and packaging techniques.

Monolithic sampler

A pulse compressor consisting of a loaded transmission line having a pluraltiy of sections which have a ratio of dispersion to nonlinearity that decreases in the direction of pulse transmission.

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Milpitas, CA, United States of America

Chung-Yi Su