Abstract: A manufacturing method of compound semiconductor field effect transistor capable of enhancing a gate/drain withstand voltage includes a step of forming a channel layer by implanting ions into the surface of a semi-insulating compound semiconductor substrate and a step of performing a first thermal treatment for removing crystalline defects on the surface of the channel layer. This method also includes a step of forming a compound semiconductor epitaxial layer by use of an epitaxial method on a region covering the channel layer, a step of forming a gate electrode within a region on the epitaxial layer just above the channel layer and a step of forming a source region and a drain region in the substrate. A concentration of the impurity for forming the channel layer at an interface between the channel layer and the epitaxial layer is 45% or under of the highest concentration when forming the channel layer.

Abstract: A metal semiconductor device, in which an electrode is formed on a semiconductor substrate to form a Schottky junction therebetween, and the electrode has an oxide film having a first thickness on its upper surface and a non-oxidized portion having a second thickness from the Schottky junction. A method for producing the metal semiconductor device is also disclosed, in which a conductor layer formed on the semiconductor substrate is oxidized in a gas containing oxygen, and a capless annealing of the semiconductor substrate having the oxidized conductor layer thereon is conducted in an atmosphere containing arsenic.

Abstract: A GaAs JFET according to the present invention is formed as follows. First, an n type active layer is formed on a GaAs substrate. Then, a gate electrode containing a group II element is formed on the n type active layer. With the gate electrode being used as a mask, an n type impurity is ion-implanted in the GaAs substrate with a high concentration in a self-aligned fashion with respect to the gate electrode. Heat-treatment is then performed on the resultant structure to diffuse the group II element in the gate electrode into the n type active layer, forming a p type gate region. At the same time, the ion-implanted n type impurity is activated, forming source and drain regions.