Matsushita Electric Industrial Co., Ltd.

Matsushita Electric Co., Ltd.

Kenji Harafuji

Akihiko Ishibashi

Yuzaburo Ban

Masafumi Kubota

Noboru Nomura

Tokuhiko Tamaki

Yoshiaki Hasegawa

Kiyoshi Ohnaka

Ryoko Miyanaga

Ayumu Tsujimura

Isao Kidoguchi

Nobuyuki Otsuka

Gaku Sugahara

Mitsuhiro Ohkuni

Toshitaka Shimamoto

Ichiro Nakayama

Akio Misaka

Kenji Kawakita

Atsuhiro Yamano

Hiromitsu Hamaguchi

Takeshi Takagi

Hideo Nakagawa

Masahiro Kume

Satoshi Kamiyama

Shigenori Hayashi

Taichi Koizumi

Michinari Yamanaka

Mitsuhiro Okuni

Norimichi Anazawa

The method for fabricating a nitride semiconductor of the present invention includes the steps of: (1) growing a first semiconductor layer made of a first group III nitride over a substrate by supplying a first group III source and a group V source containing nitrogen; and (2) growing a second semiconductor layer made of a second group III nitride on the first semiconductor layer by supplying a second group III source and a group V source containing nitrogen. At least one of the steps (1) and (2) includes the step of supplying a p-type dopant over the substrate, and an area near the interface between the first semiconductor layer and the second semiconductor layer is grown so that the density of the p-type dopant locally increases.

Method for fabricating nitride semiconductor, method for fabricating nitride semiconductor device, and nitride semiconductor device

The method of fabricating a nitride semiconductor device of this invention includes plural steps of respectively growing plural nitride semiconductor layers on a substrate; and between a step of growing one nitride semiconductor layer and a step of growing another nitride semiconductor layer adjacent to the one nitride semiconductor layer among the plural steps, a step of changing a growth ambient pressure from a first growth ambient pressure to a second growth ambient pressure different from the first growth ambient pressure.

Method of fabricating nitride semiconductor device

There is provided a MQB layer as a multi-quantum barrier portion composed of well layers and barrier layers that are formed of extremely thin films having different compositions and alternately stacked. This enhances an effective barrier height by using the phenomenon that holes likely to flow from a SiGe base layer to a Si emitter layer are reflected by the MQB layer and thereby suppresses the reverse injection of the holes from the SiGe base layer into the Si emitter layer. As a result, the reverse injection of carriers is suppressed by the MQB layer even when the base doping concentration is increased, which provides a satisfactory current amplification factor and increases a maximum oscillation frequency. What results is a bipolar transistor having excellent RF characteristics such as current amplification factor, current gain cutoff frequency, and maximum oscillation frequency in a microwave band or the like.

Bipolar transistor and semiconductor device

A method for depositing a semiconductor film on a wafer by making a source gas supplied flow almost horizontally to the surface of the wafer. When a process condition, e.g., the flow velocity or pressure of the source gas, should be changed, the source gas has its velocity and/or pressure changed so that the source gas is supplied at a substantially constant flow rate.

Method and apparatus for depositing semiconductor film and method for fabricating semiconductor device

A nitride semiconductor laser device includes an n-type contact layer of n-type GaN and an n-type cladding layer of n-type Al Ga N formed on a substrate of sapphire. On the n-type cladding layer, a multiple quantum well active layer of Al Ga N/Al Ga N, a p-type leak barrier layer of p-type Al Ga N P and a p-type cladding layer of p-type Al Ga N P are successively formed. The p-type leak barrier layer has a wider energy gap than the n-type cladding layer, and the p-type leak barrier layer and the p-type cladding layer include phosphorus for making an acceptor level shallow with keeping a wide energy gap.

Semiconductor laser device

A reactive gas supplied to a chamber 1 is put into plasma by supplying radio frequency power to the chamber 1 intermittently or while repeating high and low levels alternately and a specimen A in the chamber 1 is treated by the plasma. A positive pulse-like bias voltage synchronized with a period in which the radio frequency power is not supplied or a period in which low-level power is supplied is applied to the specimen A for preventing charging.

Plasma treatment method and plasma treatment system

A reactive gas is introduced into a vacuum chamber by a gas controller so that a plasma is generated in a plasma generation region. Subsequently, high-frequency power from a high-frequency power source is applied to a sample stage in the vacuum chamber so that ions in the plasma are made incident upon the sample stage, thereby performing dry etching with respect to a sample on the sample stage. In main etching, a value of (pressure of reactive gas)/(frequency of high-frequency power) is reduced so as to reduce a scattering probability, which is the probability of ions being scattered in collision with neutral particles in a sheath region, thereby increasing the energy of ion fluxes and making the incidence directions of the ion fluxes perpendicular to a surface of the sample stage. In overetching, the value of (pressure of reactive gas)/(frequency of high-frequency power) is increased so as to increase the above scattering probability, thereby reducing the energy of the ion fluxes and tilting the incidence directions of the ion fluxes from a perpendicular to the surface of the sample stage.

Plasma generating and processing method and apparatus thereof

There is disclosed a dry etching method capable of achieving the formation of vertical line patterns and the minimization of a difference in size between an isolated line pattern and an inner line pattern. When the line width of an inner line pattern is smaller than that of an isolated line pattern and when the width of a line pattern is greater than the width of a resist pattern, at least one parameter selected from the parameter group consisting of the pressure of a raw-material gas mixture introduced into a vacuum chamber, the exhaust amount of gas discharged from the vacuum chamber, a high-frequency electric power, the frequency of the high-frequency electric power, the rate of a lateral wall protecting gas in the raw-material gas mixture and the temperature of a sample stand, is changed such that the amounts in which the line patterns are etched, are increased and that the amount in which the inner line pattern is etched, is smaller than the amount in which the isolated line pattern is etched.

Dry etching Method

Three electrodes are disposed at lateral sides of a plasma generating chamber of an etching apparatus serving as a plasma generating apparatus. A sample stage is disposed at a lower part of the plasma generating chamber, and an opposite electrode is disposed at an upper part thereof. High frequency electric power having a first frequency is supplied to the sample stage and the opposite electrode. Respectively supplied to the three electrodes 4, 5, 6 are high frequency electric powers which are oscillated by a three-phase magnetron, which have a second frequency different from the first frequency and of which respective phases are successively different by about 120.degree. from one another, thus forming a rotational electric field in the plasma generating chamber.

Plasma generating method and apparatus

A plasma generating method comprises: a first step of disposing a plurality of lateral electrodes at lateral sides of a plasma generating part in a vacuum chamber; a second step of respectively applying, to the lateral electrodes, high frequency electric powers of which frequencies are the same as one another and of which phases are different from one another, thereby to excite, in the plasma generating part, a high frequency rotating electric field to cause electrons under translational motions in the plasma generating part to present oscillating or rotating motions; and a third step of applying, to the plasma generating part, a magnetic field substantially at a right angle to the working plane of the high frequency rotating electric field, thereby to convert the translational movement of the electrons in the plasma generating part into revolving motions under oscillating or rotating motions by which the electrons revolve in the plasma generating part. The high frequency rotating electric field and the magnetic field cause the electrons in the plasma generating part to be confined therein.

Method and apparatus for generating highly dense uniform plasma in a

At lateral sides of a plasma generating part under a vacuum, first to fourth lateral electrodes are so disposed as to surround the plasma generating part. High frequency electric power is supplied to the first lateral electrode from a first high frequency power supply, high frequency electric power is supplied to the second lateral electrode from the first high frequency power supply through a first delay circuit, high frequency electric power is supplied to the third lateral electrode from the first high frequency power supply through the first delay circuit and through a second delay circuit, and high frequency electric power is supplied to the fourth lateral electrode from the first high frequency power supply through the first and second delay circuits and through a third delay circuit. Accordingly, there are respectively applied, to the first to fourth lateral electrodes, the high frequency electric powers of which frequencies are equal to one another and of which phases are successively different from one another, and there is excited, in the plasma generating part, a rotational electric field to cause electrons in the plasma generating part to present rotational motions.

Method and apparatus for generating highly dense uniform plasma by use

Magnetic coils are provided around a plasma generation chamber. To the plasma generation chamber is supplied a microwave which is generated by a microwave generator. Electron cyclotron resonance is caused by the interaction between a magnetic field produced by the magnetic coils and the microwave generated by the microwave generator, so as to accelerate electrons in the plasma generation chamber. The electrons thus accelerated generates a plasma. A reaction chamber is provided underneath the plasma generation chamber. The plasma generated in the plasma generation chamber is introduced to the reaction chamber to be used for etching a material on a sample stage. A reflex klystron is used as the microwave generator. By changing the cavity length of the reflex klystron, the resonance frequency of the cavity resonator is varied, thus modulating the frequency of the microwave supplied to the plasma generation chamber by the microwave generator.

Growing community of inventors

Osaka, Japan

Kenji Harafuji