摘要:
A power semiconductor device having current detecting function comprising a detection pert that includes the elements of a better reach-through withstand voltage capability than those of a principal current part. The power semiconductor device comprises such elements as DMOS, IGBT or BPT cells. One area of the device acts as the detection part and another as the principal current part. The detection part and the principal current part share as their common electrode a high density substrate having a low density layer of a first conductivity type. The surface of the low density layer carries a principal and a subordinate well region of a second conductivity type each. The surface of the principal well region bears a surface electrode region of the first conductivity type acting as the other electrode of the principal current part; the surface of the subordinate well region carries a surface electrode region of the first conductivity type acting as the other electrode of the detection part. The subordinate well region is made shallower than the principal well region illustratively by use of a mask having narrower apertures through which to form the former region. This causes a reach-through to occur in the principal current part with its well region having a shorter distance to the high density substrate, and not in the detection part with its well region having a longer distance to the substrate.
摘要:
A power semiconductor device having a current detecting function comprising a detection part that includes the elements of a better reach-through withstand voltage capability than those of a principal current part. The power semiconductor device comprises such elements as DMOS, IGBT or BPT cells. One area of the device acts as the detection part and another as the principal current part. The detection part and the principal current part share as their common electrode a high density substrate having a low density layer of a first conductivity type. The surface of the low density layer carries a principal and a subordinate well region of a second conductivity type each. The surface of the principal well region bears a surface electrode region of the first conductivity type acting as the other electrode of the principal current part; the surface of the subordinate well region carries a surface electrode region of the first conductivity type acting as the other electrode of the detection part. The subordinate well region is made shallower than the principal well region illustratively by use of a mask having narrower apertures through which to form the former region. This causes a reach-through to occur in the principal current part with its well region having a shorter distance to the high density substrate, and not in the detection part with its well region having a longer distance to the substrate.
摘要:
A manufacturing method of a vertical DMOSFET having a concave channel structure, which does not permit the introduction of defects or contaminant into the channel part and which can make the shape of the groove uniform, is disclosed. On a surface of a (100)-oriented n.sup.- -on-n.sup.+ epitaxial wafer is formed an initial groove by chemical dry etching. The grooved surface is then oxidized by LOCOS technique to form a LOCOS oxide film, whereby the concave structure is formed on the epitaxial wafer. The concave width is set to be at least twice the concave depth, and the sidewall angle is set to be approximately 50.degree. to make the sidewall plane (111) of high channel mobility plane. Following this process, p-type and n-type impurities are diffused from the main surface using the LOCOS oxide film as a double diffusion mask to form a body region and a source region.
摘要:
A manufacturing method for a semiconductor device, which can attain a low ion voltage in a manufacturing method for a semiconductor device involving a process for forming a groove by etching prior to selective oxidation, selectively oxidizing a region including the groove and thereby making a channel part of the groove, is disclosed. A groove part is thermally oxidized by using a silicon nitride film as a mask. A LOCOS oxide film is formed by this thermal oxidation, and concurrently a U-groove is formed on the surface of an n.sup.- -type epitaxial layer eroded by the LOCOS oxide film, and the shape of the U-groove is fixed. A curve part formed during a chemical dry etching process remains as a curve part on the side surface of the U-groove. Then, an n.sup.+ -type source layer is formed by means of thermal diffusion to a junction thickness of 0.5 to 1 .mu.m, and a channel is set up as well. The junction depth obtained by this thermal diffusion is set up more deeply than the curve part which is formed during the above etching and remains on the side surface of the U-groove after the above selective thermal oxidation.
摘要:
A vertical type power MOSFET remarkably reduces its ON-resistance per area. A substantial groove formation in which a gate structure is constituted is performed beforehand utilizing the LOCOS method before the formation of a p-type base layer and an n.sup.+ -type source layer. The p-type base layer and the n.sup.+ -type source layer are then formed by double diffusion in a manner of self-alignment with respect to a LOCOS oxide film, simultaneously with which channels are set at sidewall portions of the LOCOS oxide film. Thereafter the LOCOS oxide film is removed to provide a U-groove so as to constitute the gate structure. Namely, the channels are set by the double diffusion of the manner of self-alignment with respect to the LOCOS oxide film, so that the channels, which are set at the sidewall portions at both sides of the groove, provide a structure of exact bilateral symmetry, there is no positional deviation of the U-groove with respect to the base layer end, and the length of the bottom face of the U-groove can be made minimally short. Therefore, the unit cell size is greatly reduced, and the ON-resistance per area is greatly decreased.
摘要:
A manufacturing method of a MOSFET having a channel part on the side surface of a groove, which does not permit the introduction of defects or contaminant into the channel part and which can make the shape of the groove uniform. An n.sup.- -type epitaxial layer having a low impurity concentration is formed on a main surface of an n.sup.+ -type semiconductor substrate. This surface is specified as a main surface, and chemical dry etching is applied to a specified region of this main surface. A region including a surface generated by the chemical dry etching is selectively oxidized to form a selective oxide film to a specified thickness. Following this process, p-type and n-type impurities are doubly diffused from the main surface to define the length of the channel and form a base layer and a source layer. Furthermore, the n.sup.+ -type semiconductor substrate is specified as a drain layer. After the double diffusion, a gate electrode is formed through a gate oxide film and a source electrode and a drain electrode are formed.
摘要:
A power semiconductor device constituted of a MOSFET incorporating a current detecting function for detecting current making use of a voltage drop developed across a channel resistance in which variations in the channel resistance due to its temperature and the gate voltage are compensated for and thereby highly accurate current detection is achieved.
摘要:
In a BRE300, an RF interface for transmitting and receiving an RF signal is used for communication with a MDE 200 and a digital signal interface for transmitting and receiving a digital signal in accordance with CPRI is used for communication with BDE 300. The BRE 300 includes a monitoring signal interface configured to notify the MDE 200 of a monitoring signal indicating a state of the radio unit 50. The signal transmitted and received through the monitoring signal interface is a ground signal and is of type different from types of signals transmitted and received by the RF interface and the digital signal interface.
摘要:
A wavelength selective switch for suppressing degradation of pass band characteristics when the temperature rises. The wavelength selective switch includes a spectroscopic element for separating input light and providing angular dispersion depending on wavelengths, a collective lens for gathering light output from the spectroscopic element, and a movable reflection block which includes a plurality of mirrors arranged in the direction of angular dispersion made by the spectroscopic element, changes the angles of the mirrors in a direction differing from the direction of angular dispersion, and reflects the light coming from the collective lens. The collective lens is fixed at one end with respect to the direction of angular dispersion, expands with heat in a direction in which it is not fixed when the temperature rises, and outputs the light in a direction opposite to the direction in which the angle of light output from the spectroscopic element changes.
摘要:
An active layer having a p-type quantum dot structure is disposed over a lower cladding layer made of semiconductor material of a first conductivity type. An upper cladding layer is disposed over the active layer. The upper cladding layer is made of semiconductor material, and includes a ridge portion and a cover portion. The ridge portion extends in one direction, and the cover portion covers the surface on both sides of the ridge portion. A capacitance reducing region is disposed on both sides of the ridge portion and reaching at least the lower surface of the cover portion. The capacitance reducing region has the first conductivity type or a higher resistivity than that of the ridge portion, and the ridge portion has a second conductivity type. If the lower cladding layer is an n-type, the capacitance reducing region reaches at least the upper surface of the lower cladding layer.