Nec Corporation

Nec Electronics Corporation

Kikuo Makita

Masayoshi Tsuji

Junichi Fujikata

Tsutomu Ishi

Toshio Baba

Takeshi Nakata

Keishi Oohashi

Toshitaka Torikai

Kazuhiro Shiba

Akiko Gomyo

Atsushi Shono

Disclosed is a method for manufacturing a semiconductor light-receiving device having high reproducibility and reliability. Specifically disclosed is a semiconductor light-receiving devicewith a mesa structure wherein a light-absorbing layer, an avalanche multiplication layerand an electric-field relaxation layerare formed on a semiconductor substrate. The light-absorbing layer, avalanche multiplication layerand electric-field relaxation layerexposed in the side wall of the mesa structure are protected by an SiNfilm or an SiONfilm. The hydrogen concentration in the side wall surface of the electric-field relaxation layeris set at not more than 15%, preferably not more than 10% of the carrier concentration of the electric-field relaxation layer

Method for manufacturing a semiconductor light-receiving device

A Schottky photodiode includes a semiconductor layer and a conductive film provided in contact with the semiconductor layer. The conductive film has an aperture and a periodic structure provided around said aperture for producing a resonant state by an excited surface plasmon in a film surface of the conductive film by means of the incident light to the film surface. The photodiode detects near-field light that is generated by at the interface between the conductive film and semiconductor layer the excited surface plasmon. The aperture has a diameter smaller than the wavelength of the incident light.

Method for fabricating photodiodes

Photodiode and method for fabricating same

In a semiconductor photo-detecting element (an avalanche photodiode), a high-sensitivity element is obtained by incorporating a multiplication layer having high-performance multiplication characteristics. By using a structure which reduces an electric field applied to an etching stopper layer, it is possible to use a multiplication layer having higher-performance multiplication characteristics (a multiplication layer which performs multiplication with a high electric field). The first method to realize this is to use a conductivity type multiplication layer. The second method is to use a structure in which a field buffer layer of the second conductivity type is incorporated. As a result of the use of these methods, a structure which applies an electric field lower than the multiplier electrical field to the etching stopper layer is obtained.

Semiconductor photo-detecting element

A light control apparatus includes a part for splitting an input light entering the light control apparatus through an optical fiber, a photoelectric conversion part for converting a monitor light into an electrical signal, and a third part for controlling the opening and closing of an optical transmission path for a signal light based on the electrical signal. The light power of an output light is controlled by the opening and closing amount of the optical transmission path which is controlled depending on the amount of the electrical signal output in accordance with the level of the monitor light. A semiconductor photovoltaic device capable of performing photoelectric conversion without using an external power source is used as the photoelectric conversion part. An optical shutter using a micromachine, or an optical device such as absorption-type modulator or refractive index-type modulator is used as the third part.

Light control apparatus having a device for controlling the input signal light of an optical transmission path

The invention provides a method for selective growth of semiconductor crystals, including the step of forming a semiconductor layer in a selected region of a semiconductor substrate by using a mask, the semiconductor layer being controlled with respect to atomic ordering or natural super lattice (NSL). It is possible by the invention to control the energy gap, optical anisotropy and electrically conductive anisotropy of a semiconductor layer, and also possible by the invention to carry out two-dimensional control of material properties in a substrate in accordance with a pattern of a mask.

Method for semiconductor crystal growth

An avalanche photodiode is provided which consists of a staircase APD with a periodic multilayer structure graded in composition from InAlAs to InGa.sub.x Al.sub.(1-x) As (x&gt;0.1) as the multiplication layer to improve the dark current characteristic. Another photodiode with separate photoabsorption and multiplication regions is provided with an electric-field relaxation layer whose bandgap is wider than that of the photoabsorption and has a triple structure with a highly-doped layer sandwiched between lightly-doped layers. This photodiode incorporates in detail on an n-type InP substrate, an avalanche multiplication layer 13 of a periodic multilayer structure graded in composition from n.sup.- -InAlAs to InGa.sub.x Al.sub.(1-x) As, a p.sup.- -InGaAs photoabsorption layer 17, and an InP electric-field relaxation triple layer 16 consisting of n.sup.-, p.sup.+, and p.sup.- layers between the avalanche multiplication layer 13 and the photoabsorption layer 17.

Staircase avalanche photodiode

A semiconductor optical device such as a light modulator or a tunable laser emitting diode has either light absorbing/transmitting layer, light modulation layer or tuning layer responsive to an electric field for changing the intensity or the wavelength of an output light, and the light absorbing/transmitting layer, the light modulation layer or the tuning layer is implemented by a super-lattice structure formed by using a first compound semiconductor material and a second compound semiconductor material, wherein the second compound semiconductor material is larger in electron affinity as well as the total of electron affinity and energy band gap than the first compound semiconductor material so that a large extinction ratio or a wide variation in wavelength is achieved.

Semiconductor optical device with light controlling layer of

On a p-type InP substrate 12, there are provided a p-type InGaAs light absorptive layer 14 and an InAlAs/InGaAs superlattice avalanche multiplier layer 15. By selecting the composition of the well layer and the barrier layer of the avalanche multiplier layer 15, a strain is applied to at least one of them so that the difference .DELTA. Ec between the energies at the lower end of the conduction band of the well layer and/or the barrier layer is increased, or the difference .DELTA. Ev between the energies at the upper end of the valence band of the well layer and/or the barrier layer is decreased, and/or the effective mass of the hole within the well layer and/or barrier layer is decreased. Thus, the ionization factor ratio is further improved, or the pile-up of the hole is alleviated, or the traveling time of the hole is shortened to achieve an avalanche multiplier semiconductor photodetector having a wide bandwidth, low noise and high response characteristic.

Semiconductor photodetector using avalanche multiplication and strained

An avalanche photodiode includes an avalanche multiplication layer of a hetero-periodical structure consisting of alternately provided barrier and well layers. Each barrier layer includes a multi-quantum barrier layer consisting of alternately provided short-width barrier and well layers. The barrier and well layers include respectively first and second III-group elements which meet the following conditions:

Avalanche photodiode with hetero-periodical structure

An avalanche photodiode includes an avalanche multiplication layer consisting of a superlattice multilayer structure in which a repeated thin multilayer of short-width well layers and short-width barrier layers is sandwiched between a well layer and a barrier layer. The width of the short-width well and barrier layers is preferably up to 100 .ANG.. In such a structure, an ionization rate of electrons in the avalanche multiplication layer increases, so that the avalanche photodiode has low-noise and high speed response performances.

Growing community of inventors

Tokyo, Japan

Kikuo Makita