Nec Corporation

Nippon Telegraph and Telephone Corporation

Kajima Corporation

Ocean Cable Co., Ltd.

Akira Mochizuki

Hiroshi Adachi

Hiroaki Tsutsui

Nobuyuki Yoshizawa

Takeshi Imai

Masakuni Okubo

Tadayoshi Muta

Hisato Katayama

Kazumasa Nemoto

Kouki Yamaguchi

Yasuo Ishino

Masami Suzuki

Tadatoshi Tanifuji

In a recessed structure MESFET, an active layer (n-type layer) 2 is provided on a high resistance GaAs substrate 1, a pair of contact layers (n.sup.+ -type layers) 31, 32 is provided on the active layer 2, a source electrode 6 is provided on one contact layer 31, a drain electrode 7 is provided on the other contact layer 32 and a gate electrode 5 is provided on the active layer 2 to achieve a recessed structure. A semiconductor layer 4 having a lower impurity density than that of the contact layer 31, 32 is formed at the recess edge portion at at least drain side to alleviate the concentration of the electric field and current there to suppress the generation of electron-holes pairs by collision ionization to reduce the damage to the crystal lattice by non-luminescence recombination of the electron-holes thus preventing the degradation of the FET characteristics.

Semiconductor MESFET device with edge portion

The invention provides a method of forming a gate electrode on a channel layer in a field effect transistor. A first layer made of a first metal having a heat resistivity is formed on a gate formation region of a surface of a channel layer on a semiconductor substrate. The substrate is subjected to a heat treatment so as to recover a damage of the channel layer caused by the formation of the first layer. A second layer made of a second metal having a heat resistivity is formed on a surface of the first layer. A third layer made of a third metal having a low electrical resistivity is formed on a surface of the second layer thereby a gate electrode comprising the first, second and third layers is formed on the channel layer free from any damage caused by the formation steps.

Method of fabricating a multi-layer gate electrode with annealing step

A submarine, optical-fiber cable having a central metal wire, a slotted rod surrounding the wires, an absorbent sheath surrounding the slotted rod, a plurality of strength members helically wound around the absorbent sheath, a metal jacket surrounding the strength members, and a plastic sheath surrounding the metal jacket. The slotted rod includes peripheral helical slots, and each of the slots may receive at least one optical fiber or at least one optical ribbon. The optical ribbon includes at least two optical fibers. Each of the optical fibers has a tensile strain ranging from about 0.015 to 0.3% along its axis. The absorbent sheath includes a layer surrounding and contacting the slotted rod for absorbing water. The cable is suitable for operating in deep sea beds for a long period of time, for laying and recovering cables, and for quick repair. Modulated strain distribution in the optical fibers suppresses stimulated Brillouin scattering therein.

Submarine, optical-fiber cable with optical fibers having tensile strain

A clean room is adapted to provide a plurality of clean air zones with different degrees of cleanliness. Air is passed through high efficiency particulate air filters in the ceiling of the room and withdrawn through shutters in the floor of the room. The shutters are adjustable to maintain a pressure-balanced system. The room is divided by walls and partitions to define different zones which are filtered by different classes of filters depending on the degree of cleanliness required in each zone.

Clean room having partially different degree of cleanliness

Growing community of inventors

Tokyo, Japan

Akira Mochizuki