Agency of Industrial Science and Technology

Taiyo Yuden Co., Ltd.

Ministry of International Trade & Industry

Agency of Industrial Science and Technology Ministry of International

Mitsuyuki Yamanaka

Yutaka Hayashi

Hideyo Iida

Toshio Mishuku

Hideyuki Karasawa

Takashi Yoshimi

A method for forming a thin semiconductor film comprises the steps of supplying on a surface of a heated substrate a first material gas composed of germanium halide or germanium hydro-fluoride obtained by partially substituting fluorine of the germanium fluoride together with a second material gas composed of silicon hydride or silicon fluoro-hydride obtained by partially substituting hydrogen of the silicon hydride with fluorine and causing a chemical reaction between the first and second material gases, thereby growing a thin film containing germanium over the surface of the substrate. By controlling the substrate temperature or flow rate ratio of the first material gas to the second material gas, an optical gap of the thin film grown can be controlled.

Method for forming a thin semiconductor film

A process for depositing a thin semiconductor film includes the steps of depositing a thin film on a substrate by feeding onto the surface of the substrate being heated a gaseous starting material containing a constituent element of the thin film, and feeding excited hydrogen to the thin film without exposing the thin film to the ambient air. Disilane was fed together with hydrogen carrier gas onto a quartz substrate to deposit thereon a thin amorphous silicon film, to which excited hydrogen from a hydrogen plasma was then fed to modify the deposited thin silicon film. As a result, the photoconductivity of the thin silicon film was improved.

Process for depositing a thermal CVD film of Si or Ge using a hydrogen

A thin film field effect transistor comprising a source electrode and a drain electrode joined to a first semiconductor layer respectively through first and second portions of a second doped semiconductor layer, a gate insulating layer, and a gate electrode capacity-coupled through the gate insulating layer with a portion of the first semiconductor layer, in which a channel is formed, corresponding to a gap between the source electrode and the drain electrode. A doped intermediate semiconductor layer is formed in contact with the channel in the first semiconductor layer. The gate threshold voltage of the thin film field effect transistor can be varied by selectively varying the thickness of the doped intermediate semiconductor layer. Thus, a plurality of thin film field effect transistors respectively having different gate threshold voltages can be formed on a single substrate simply by forming the doped intermediate semiconductor layers for the thin film field effect transistors with different thicknesses.

Thin film field effect transistor and a method of manufacturing the same

A thin-film solar cell has a two-layered transparent electrode formed on a transparent substrate, a photoelectric conversion section formed on the transparent electrode, and a back electrode formed on the photoelectric conversion section. The first layer of the transparent electrode is formed on the transparent substrate and is constituted of crystal grains having a large average diameter, while the second layer thereof is formed on the first layer and is constituted of crystal grains having a small average grain diameter. The sharp pointed tips of the coarse crystal grains of the first layer are covered by the fine crystal grains of the second layer so that the side of the transparent electrode in contact with the photoelectric conversion section presents a relatively smooth surface with rounded irregularities. Each layer is separately deposited on the respective transparent substrate.

Thin-film solar cell

In the deposition of a hydrogen-containing semiconductor film on a metal substrate, the electric contact characteristic between the metal substrate and the semiconductor film is improved by preparatorily exposing to hydrogen plasma the surface of the metal substrate on which the semiconductor film is to be deposited.

Growing community of inventors

Taukuba, Japan

Mitsuyuki Yamanaka