Hewlett-packard Company

Ghulam Hasnain

Chung-Yi Su

James N Hollenhorst

Shih-Yuan Wang

Michael R Tan

Albert T Yuen

Jeffrey N Miller

Yu-Min Houng

Gottfried H Dohler

A substantially n-type substrate structure having a p-type surface for use in semiconductor devices as a substitute for a p-type semiconductor substrate. The substrate structure comprises a substrate region and a buffer region. The substrate region is a region of n-type compound semiconductor, and includes a degeneratively n-doped portion adjacent its first surface. The buffer region is a region of compound semiconductor doped with a p-type dopant. The buffer region is located on the first surface of the substrate region and includes a surface remote from the substrate region that provides the p-type surface of the substrate structure. The buffer region also includes a degeneratively p-doped portion adjacent the degeneratively n-doped portion of the substrate region. The substrate structure includes a tunnel junction between the degeneratively n-doped portion of the substrate region and the degeneratively p-doped portion of the buffer region. The substrate structure is made by degeneratively doping a substrate region of n-type compound semiconductor material adjacent its first surface with an n-type impurity, and depositing a layer of compound semiconductor material doped with a p-type impurity on the first surface of the substrate region to form a buffer region that includes a surface remote from the substrate region. In the course of depositing the compound semiconductor material to form the buffer region, the compound semiconductor material is degeneratively doped with the p-type impurity at least in a portion adjacent the substrate region to form a tunnel junction between the substrate region and the buffer region.

N-drive, p-common light-emitting devices fabricated on an n-type

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 molecular beam epitaxy (MBE) process in which some portions of the substrate are shadowed by a shadow mask from receiving at least one of the molecular beams used in the MBE process. This process is capable of producing NIPI superlattices that have selective contacts that are far superior to those which can be produced at present. This technique can also produce a wide variety of NIPI devices as well as other types of IC structures.

Growing community of inventors

Stanford, CA, United States of America

Ghulam Hasnain