METHOD OF GROWING A DOPED III-V ALLOY LAYER BY MOLECULAR BEAM EPITAXY AND A SEMICONDUCTOR DEVICE COMPRISING A SEMICONDUCTOR SUBSTRATE BEARING AN EPITAXIAL LAYER OF A DOPED III-V ALLOY GROWN BY SUCH A METHOD

摘要

A method of growing III-V alloy layers by a molecular beam epitaxy process. Difficulties have been experienced when growing doped III-V alloy layers by conventional molecular beam epitaxy processes due to the introduction of electron or hole traps which impair the electrical and optical properties of the alloy. Such III-V alloy layers are used in making microwave and opto-electronic semiconductor devices such as field effect transistors and laser diodes.
In the present invention, an epitaxial layer (48) of a doped III-V alloy is grown on a semiconductor substrate (1) by placing the substrate (1) in a vacuum chamber (3), reducing the pressure in the vacuum chamber (3) to below atmospheric pressure, maintaining the substrate (1) at a temperature inthe range from 300 to 500 DEG C, and directing a plurality of molecular beams containing the constituent elements of the doped III-V alloy and a molecular beam of lead onto the heated substrate (1). The magnitude of the lead flux is sufficient to form and maintain a presence of from 5 to 20% of a monolayer of lead on the growth surface..