Heterjunction bipolar transistor with tunnelling mis emitter junction

Abstract

A method and structure are provided for a high performance heterojunction bipolar transistor which is suited to compound semiconductor systems such as gallium arsenide (GaAs) and which utilises an emitter junction formed from a plurality of metal layers and a plurality of ultra-thin insulating layers. The metal layers chosen have work functions which form a tunnelling Metal-Insulator-Semiconductor Junction when deposited on top of an ultra-thin insulating layer. The insulating layer may be made from a rare-earth oxide such as gadolinium oxide (Gd2O3) which is epitaxially grown on a compound semiconductor substrate and possibly covered with a second ultra-thin insulating layer.

Description

technical field [0001] The present invention generally relates to integrated circuits. More specifically, the present invention provides a fabrication method and structure for a metal-insulator-semiconductor (MIS) transistor structure including compound semiconductor materials. However, it should be understood that many variations, changes and substitutions are possible. It will be convenient to describe the invention hereinafter in relation to a MIS heterojunction bipolar transistor (HBT) comprising a GaAs substrate, however, it should be understood that the invention is not limited to this use. Background technique [0002] The present invention has identified the following background of the invention and related art. Over the years, device designers have recognized the importance of bandgap engineering techniques in designing transistor devices (devices) for high performance applications. As known in the art, bandgap engineering is the technique of fabricating semicond...

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Problems solved by technology

While silicon dioxide is known to form a good passivation layer on silicon, equivalent passivation materials for compound semiconductors such as gallium arsenide have not been reported for many years

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