USA As Represented by Secretary of the Navy

Walter Kruppa

Brian R Bennett

John Bradley Boos

Doewon Park

Ming-Jey Yang

J Brad Boos

This invention pertains to more sensitive and more stable electronic devices which can sense electrical and magnetic fields. The devices are characterized by InAs channels confined on both sides thereof by a wide band gap AlSb material; protective layers above the AlSb material; modulation doping above the AlSb material; and layers of the InAs channel material containing 1 to 99 mol percent antimony, with the channel material being deposited in the form of alternating monolayers of InSb and InAs, of a ternary mixture of InAsSb.

Modified InAs hall elements

Heterostructure field-effect transistors (HFETs) and other electronic devs are fabricated from a series of semiconductor layers to have reduced impact ionization. On to a first barrier layer there is added a unique second subchannel layer having high quality transport properties for reducing impact ionization. A third barrier layer having a controlled thickness to permit electrons to tunnel through the layer to the subchannel layer is added as a spacer for the fourth main channel layer. A fifth multilayer composite barrier layer is added which has at least a barrier layer in contact with the fourth channel layer and on top a sixth cap layer is applied. The device is completed by adding two ohmic contacts in a spaced apart relationship on the sixth cap layer with a Schottky gate between them which is formed in contact with the fifth barrier layer. The second subchannel layer and the fourth main channel layers are made of materials which have the proper respective energy gaps and ground state energies such that during use the transfer of hot electrons from the main channel into the subchannel is made probable to reduce impact ionization in the main channel. In the preferred AlSb/InAs-based HFETs, the use of an Is InAs subchannel layer under the main InAs channel improves the performance of the HEMTs particularly for gate lengths in the deep-submicron regime. The devices exhibit higher transconductance, lower output conductance, reduced gate leakage current, higher operating drain voltage, and improved frequency performance.

Channel design to reduce impact ionization in heterostructure

An electronic device characterized by a GaAs substrate and a base disposed n the substrate, the base comprising InAs channel layer, AlSb layer above the channel layer, In.sub.x Al.sub.1-x As.sub.y Sb.sub.1-y layer containing at least In, Al, and As disposed above the AlSb channel layer, InAs cap layer disposed above and in contact with the In.sub.x Al.sub.1-x As.sub.y Sb.sub.1-y layer disposed below the InAs channel layer and in contact with the substrate, p.sup.+ GaSb layer disposed within the AlSb layer, Schottky gate with a pad disposed on and in contact with the In.sub.x Al.sub.1-x As.sub.y Sb.sub.1-y layer, at least one ohmic contact disposed on the InAs cap layer, and a trench extending through the base to the substrate isolating the gate bonding pad from the device and providing a gate air bridge which prevents contact between the gate and the InAs layer. The gate air bridge fabrication is accomplished by a liquid etchant containing more than half, on volume basis, of concentrated lactic acid or acetic acid with remainder hydrogen peroxide and concentrated hydrofluoric acid. The etchant attacks InAs, In.sub.x Al.sub.1-x As.sub.y Sb.sub.1-y, AlSb, and GaSb but does not attack GaAs and Au-based alloys.

Electronic devices with InAlAsSb/AlSb barrier

A heterojunction device, and a method for producing the device. A gate air bridge is formed at the mesa sidewall between the active region and the gate bonding pad to lower the gate leakage current. The device has a double recessed gate to reduce local fields in the vicinity of the gate. The fabrication method uses dielectric intermediate and final passivation layers to optimize the double-recess profile and control the extension of the high-field region between the gate and the drain. This combination increases the breakdown potential of the device, but minimizes the effective gate length of the device, preserving high frequency performance.

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Fairfax Station, VA, United States of America

Walter Kruppa