Fujitsu Corporation

Shigeru Okamura

Tomonori Ishikawa

Takao Taguchi

A semiconductor device with a FET utilizing a two-dimensional electron gas (2DEG), including a substrate, a first semiconductor layer (an undoped GaAs layer) formed on the substrate by an MBE method, a second semiconductor layer (an n-type AlGaAs layer) formed on the first layer by an MBE method, a source electrode and a drain electrode formed on the second layer and having alloyed regions, and a gate electrode formed on the second layer. To decrease the contact resistance between the alloyed regions and the 2DEG layer in the first layer, impurity doped regions are formed in the first layer under the source electrode and the drain electrode by an ion-implantation method, prior to the formation of the second layer. Further, an internal conductive line or resistor can be formed by doping impurities into the first layer by an ion-implantation method prior to the formation of the second layer.

Method for producing semiconductor device

High electron mobility heterojunction semiconductor devices provided with a means to cause exposure of the electron source layer thereof to an electromagnetic wave allows modulation, adjustment and the like of the characteristics thereof even after completion of the production thereof, thus realizing a considerable magnitude of flexibility in the characteristics as well as considerably different modes in various embodiments, including field effect transistors which allow modulation of threshold voltage etc., connection channels or capacitors having a smaller resistance, programmable memory devices, image sensors. In addition, the high electron mobility heterojunction semiconductor devices can have a much higher operation speed than those available in the prior art.

High electron mobility heterojunction semiconductor devices

This invention relates to an ion implantation apparatus and method for maskless processing of substrate, and more particularly, to form ion implanted pattern by selectively scanning a focused ion beam on the surface of a processing substrate. The timing of the apparatus is controlled by a variable frequency clock pulse. By using the variable frequency oscillator, a clock frequency can be controlled continuously. So, the ion implantation pattern is easily controlled by the clock frequency and scanning number with high accuracy compared to a prior art.

Growing community of inventors

Ebina, Japan

Shigeru Okamura