JPS5917276A - Semiconductor device - Google Patents

Abstract

PURPOSE:To offer the semiconductor device excluded with conduction noise, avalanche noise and moreover, easy to manufacture by a method wherein the device is constructed of semiconductor pellets of the plural sheets having P-N junctions and to perform high-frequency action and laminated between a pair of electrodes arranging the rectifying directions thereof, and a high resistor consisting of a semiconductor interposed between the electrodes adjoining to the cathode side thereof. CONSTITUTION:Depletion layers are formed though a little in P-N junctions of the respective silicon pellets 4a-4n to make junction capacitances to exist, and when a voltage is applied, and junction capacitances are charged to reach conduction, a time constant expressed by the product of junction capacitance and resistance is enlarged because of interposition of the high resistor 6, and forward recovery time is elongated. Accordingly, the current rise rate di/dt at forward recovery time is reduced, a counter electromotive voltage is reduced, and conduction noise is not generated. Moreover, when a reversely directional voltage is applied, the avalanches are generated locally in the silicon pellets 4a-4n on the anode side because of ununiformity of the alloted voltage rate, and even when pulse noise is generated, because the peak value thereof is limited by the high resistor 6, it is not transmitted to a Braun tube as avalanche noise.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device, and in particular, what is done with a pn junction?
The present invention relates to a high-voltage semiconductor device in which several semiconductor pellets are laminated and bonded together with a solder material with their rectifying directions aligned, and the periphery is molded with an insulating material.

This type of high-voltage semiconductor device is often used as a rectifier in the horizontal deflection circuit of a television receiver to rectify the high-voltage output of a flyback transformer and supply it to a cathode ray tube. Since it is necessary to perform high frequency operation, each semiconductor pellet is doped with a lifetime killer such as gold or platinum, and the forward recovery time and reverse recovery time are respectively 500n.
In some cases, the forward recovery time has been shortened to 8ec, 100ns (a) or less, and due to the current rise rate di/dt during forward recovery and the stray inductance L of the circuit, dl.

The back electromotive force e (=-LX-a-T) appears as noise, propagates to the tuner circuit, and causes bad shadows on the CRT screen.
(hereinafter, this noise will be referred to as conduction noise).

Further, when a reverse voltage of 1 is applied to the surface pressure semiconductor device, the voltage is not evenly distributed to each semiconductor pellet due to the floating B-11k. If this non-uniformity is expressed in terms of voltage sharing ratio, the voltage sharing ratio is high on the anode side and low on the cathode side.

When a voltage higher than the reverse breakdown voltage is applied to the semiconductor pellet on the anode side, the semiconductor pellet reaches the alancier region and locally causes avalanche. The current that flows at this time flows from the floating valley through the avalanche-generated semiconductor pellet to the flyback transformer, but since avalanche occurs rapidly,
It is transmitted as pulse noise to the cathode side through the junction capacitance of the semiconductor bullet that has not caused avalanche, and is also transmitted to the tuner circuit, causing the cathode ray tube picture
1 (hereinafter, this noise will be referred to as avalanche noise).

Conventionally, attempts have been made to use a combination of semiconductor pellets to which different lifetime killers have been added in order to reduce conduction noise, and to increase the number of stacked semiconductor pellets to reduce avalanche noise, but these efforts have not been sufficient. I can't say it,
In addition, VA adjustment of the process conditions could not be achieved and the manufacturing process was complicated.

Therefore, an object of the present invention is to provide a semiconductor device that can eliminate both conduction noise and avalanche noise and is easy to manufacture.

A feature of the present invention that achieves the above object is (3) that a high-resistance element is interposed on the cathode side.

Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

In FIG. 1, 1 indicates the high voltage semiconductor device according to the present invention as a whole, and 2a and 2b are TJ tffi made of tungsten or molybdenum, with copper as the main component.
3a, 31) are percussion welded. Between the electrodes 2a and 2b, a plurality of silicon pellets 4a, 4b, . . . , 4n having pn junctions are stacked with their rectifying directions aligned. - As an example, [Yf 2 a to electrode 2
The rectification direction is aligned in the direction toward b. Therefore, the electrode 2a is an anode side electrode, and the electrode 2b is a cathode side RI electrode. There is a p
The silicon spacer 5 that does not form an n-junction is
A silicon high-resistance element 6 having no pn junction is interposed between the silicon bezels 2b and 4n. W, each member from the pole 2a to the electrode 2b is bonded by aluminum solder (not shown). The periphery of this laminated adhesive body is molded with glass 7 from one electrode 2a to the other t-electrode 2b. The glass 7 has a surface stabilizing function for the silicon pellets 4a, 4b, .

Each silicon vent (4a, 4b...4n) has a pin structure, and platinum is added as a lifetime killer. The silicon spacer 5 has p-type conductivity, and has a specific resistance of 0.01 Ω-(1) or less, and a resistance value of about 70 mΩ at most, so it can be regarded as a conductor. The high resistance element 6 has n-type conductivity, and its specific resistance is approximately 100.
0Ω-(7). In order to prevent the formation of a p-type regrowth layer on the surface of the aluminum solder during bonding, an n-type product concentration layer is formed on the surface. The resistivity of the resistivity of about 1000Ω-(7) sandwiched between the high concentration layers is about 10
Ω ■ (has an anti-value.

This high voltage semiconductor device 1 is manufactured as follows.

First, a bonded body of silicon pellets 4a, 4b, . . . , 4n, silicon spacer 5, and silicon high resistance material is obtained. At this time, the cross sections are aligned in the (product)@ direction to form a rod shape.

On the other hand, leads 3a are attached to the electrodes 2a and 2b.

Prepare a welded electrode 3b and use it as the electrode 2a.

The rod-shaped laminated adhesive obtained earlier is placed between 2b and further integrated with aluminum solder. ZnO-B2O35i0
A slurry of 2-series glass is spread over this integrated product and heated to form molded glass 7.

Silicon pellets 4a, 4n, spacer s, high resistance element 6
Since they are made of the same material, no thermal strain is applied to silicone 4a and 4b. Also, when sintering the glass slurry, bubbles are likely to form in the space A between the RL electrodes a, 2b, the spacer 5, and the high-resistance element 6.
4a, 4n are not reached, so silicon ben) 4a
, 4n characteristics do not deteriorate.

Next, the function of the high resistance body 6 will be explained.

When a forward voltage is applied to the electrode 2b so that the electrode 2a is in the positive position, each silicon pellet 4a.

After a forward recovery time of 4b...4n, a forward current flows.

In a state where no voltage is applied, a slight depletion node is formed in the pn junction of each silicon belenium 4a, 4b, . . . , 4n, and a junction capacitance exists. ft pressure is applied, the junction capacitance is charged and conduction is reached, but the recovery time, that is, the charging time, is determined by a time constant expressed by the product of the contact capacitance and the resistance.

Since the high resistance element 6 is interposed, the time constant becomes large and the normal recovery time becomes long. Therefore, the current rise rate di/dt during forward recovery becomes small, the back electromotive force C becomes small, and conduction noise does not occur.

Furthermore, when reverse circulation pressure is applied to the high-voltage semiconductor device 1, avalanche occurs locally in the silicon pellet on the anode side due to uneven pressure distribution, and even if pulse noise is generated, Since the peak value is limited by the high resistance element 6, even if it propagates to the tuner circuit, it will not be transmitted to the cathode ray tube as avalanche noise.

FIG. 2 shows the phase relationship between the output magnetic pressure waveform 21 of the flyback transformer and the video signal voltage waveform 220 of the Brown Agency when there is no signal.

The waveform indicated by a dotted line in the video signal magnetic pressure waveform 22 is a noise waveform, and 23 is due to conduction noise, 24
a-24b is due to avalanche noise.

When using a conventional high voltage semiconductor device, noise waves 23
．． 24a and 24b, but when using the high voltage semiconductor device according to the present invention, noise? 7fi23.24
a and 24b were not observed.

In the case of a high-sensitivity black-and-white television receiver in which noise is likely to appear on a cathode ray tube, it has been experimentally confirmed that noise generation can be suppressed if the resistance value of the high-resistance element 6 is 8Ω or more.

Since the average beam current flowing through the horizontal deflection circuit is small, even if the high voltage semiconductor device 1 includes the high resistance element 6,
The heat loss generated is negligible.

In order to have a resistance value of approximately 1,000Ω, the high resistance element 6 may have a length of 0.25 to 0.4B, and the high voltage semiconductor device #
1 is almost the same size as the conventional one even though it has a high resistance element 6 inside. In recent years, high-voltage semiconductor devices [d] have been assembled into flyback transformers, and the high-voltage semiconductor device 1 of the present invention is designed to meet the needs of users. Conventionally, when a current flows in the forward direction, a discharge occurs between the exposed part of the cathode side and the ground potential part, and a large current flows through each silicon pellet 4a, 4b, . . . 4n, However, according to the present invention, the high resistance element 6 limits the current, so each of the 7 recomp pellets 4
a, 4b, . . . , 4n are spared from thermal damage and maintain a long life.

By incorporating a high resistance element 6, silicon Benz) 4a,
4b...4n can be made with the same specifications, and can be built-in simply by laminating and bonding, so manufacturing is easy.

In the past, there was no need to go to the trouble of connecting high resistance, so the requirements for the first officer were the same as above.

Next, embodiments of the present invention will be described.

([) In order for the high-resistance element 6 to also function as a spacer, it is effective to have it adjacent to the pole 2b, but if the semiconductor pellet is located on the cathode side in a region where avalanche does not occur, then , the intervening position is not restricted.

(2) The conductivity type of the high-resistance element 6 may be p-type.

(3) The insulator 7 is not limited to glass, and may be made of resin. In the case of a resin mold, it may have a dual structure of a surface stabilizing phase and a mold layer.

(4) It may be a so-called plug-in 41J without the leads 3a and 3b.

(5) The high resistance body 6 is not limited to one made of a semiconductor.

(6) The components 2a and 2b may be omitted, and the spacer 5 and the high resistance body 6 may be used as the polarizations 2a and 2b, respectively.

[Brief explanation of drawings]

FIG. 1 shows a high voltage semiconductor device showing one embodiment of the present invention.
FIG. 2 shows the output heavy pressure waveform of the flyback transformer when the high voltage semiconductor device 14 shown in FIG. FIG. 3 is a diagram showing voltage waveforms. ■...High voltage semiconductor device, 2a, 2b...Electrode, 3a
.

Claims (1)

[Claims] 1. A plurality of semiconductor pellets having a pn junction between a pair of electrodes and performing high frequency operation are stacked with their rectifying directions aligned, and a high resistance material is interposed on the cathode side,
1. A semiconductor device characterized in that a solder material is used to bond the two together, and the bonded product is molded with an insulating material. 2. The semiconductor device according to item 1, wherein the high resistance element is provided adjacent to the cathode side electrode. 3. The semiconductor device according to item 1, wherein the high resistance body is made of a semiconductor. 4. The semiconductor device according to item 1, wherein each semiconductor pellet and the high-resistance element have the same cross section in the stacking direction.