JP5658960B2 - Semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device.

  In the thyristor, simple means and technology for obtaining a low withstand voltage thyristor by disposing a low withstand voltage region having a lower withstand voltage compared to other portions in the junction is disclosed (for example, see Patent Document 1).

  On the other hand, there is a single conduction thyristor that includes a thyristor element and a diode element having the same reverse voltage direction in parallel. FIG. 7 shows a conventional single conduction thyristor using the technique disclosed in Patent Document 1. In FIG. In such a conventional single conduction thyristor (semiconductor device), when a higher voltage than the cathode is applied to the anode of the thyristor in the forward direction, a reverse voltage is applied to the junction J2. As a result, the low withstand voltage region whose junction withstand voltage is lower than that of the junction J2 breaks down first. As a result, a current path is formed through which current flows from the n ++ region of the anode part to the p ++ region of the cathode part through the low breakdown voltage region. When this current increases, a voltage drop occurs in the n + region immediately below the p ++ region of the anode part and the p− region immediately above the n + region of the cathode part due to the lateral resistance components of the n + region and the p− region of the anode part. This voltage drop causes the junctions J1 and J3 to be forward biased. By this forward bias, a transistor composed of the p ++ region, the n + region, and the p− region and a bipolar transistor composed of the n + region, the p− region, and the n + region of the cathode portion shift to a conductive state. As a result, the thyristor portion becomes conductive.

Japanese Patent Laid-Open No. 03-62571

  However, in the one-conduction thyristor shown in FIG. 7, since there is a conduction diode part in the ignition operation indicating the operation process in which the thyristor part conducts, the breakdown current of the thyristor flows through the n + region of the cathode part. Instead, it may flow to the p ++ region of the cathode part. Such an incomplete conduction state shifts to a state in which current flows from the anode part (p + region) to the cathode part (n + region) by further flowing a breakdown current. For this reason, in such a conventional single conduction thyristor, the ignition operation sensitivity indicating the magnitude of the breakdown current (breakover current) that flows when transitioning to the conduction state is lower than that of the bidirectional (symmetric characteristic) thyristor. .

  In addition, in order to increase the ignition operation sensitivity, the impurity concentration of the n + region or the p− region of the anode part may be changed. However, when the impurity concentration of the n + region or the p− region of the anode part is changed, the holding current characteristic and the breakdown voltage, which are the characteristics of the thyristor, may be affected. Therefore, it is difficult to increase the ignition operation sensitivity while maintaining the holding current characteristics and the breakdown voltage by changing the impurity concentration of the n + region and the p− region of the anode part. As described above, the one-conduction thyristor shown in FIG. 7 has a problem that it is difficult to achieve high ignition operation sensitivity without affecting the holding current characteristics and the breakdown voltage.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a single conduction thyristor (semiconductor device) that realizes high ignition operation sensitivity without affecting the holding current characteristics and the breakdown voltage. ) To provide.

In order to solve the above problem, the present invention provides a first region of a first conductivity type, a second region of a second conductivity type, a third region of the first conductivity type, and a second region of the second conductivity type. a thyristor unit and the fourth region are joined in this order, the second region and the third region have a and joined diode unit, a first semiconductor portion in contact with the second region in the diode unit A semiconductor device which is a single conduction thyristor in which a substrate surface and a portion of a second semiconductor substrate surface in contact with the third region in the diode portion are opposed to each other, the first semiconductor substrate surface and a front surface An ignition operation which is formed between the first semiconductor substrate surface and the second semiconductor substrate surface so as to face both of the second semiconductor substrate surface and indicates an operation process in which the thyristor portion is conducted. The first semiconductor substrate surface and the second semiconductor substrate. The current path flowing between the surface is a semiconductor device characterized in that it comprises a fifth region for longer than the shortest path between the first semiconductor substrate surface and the second semiconductor substrate surface.

  In addition, according to the present invention, in the above invention, the fifth region is located between the first semiconductor substrate surface and the second semiconductor substrate surface and in parallel with the second semiconductor substrate surface. A region of the second conductivity type formed with two bonding surfaces in contact with the region, wherein a region width in a direction parallel to the second semiconductor substrate surface is narrower than a width of the second semiconductor substrate surface; And formed as a part of the fourth region.

  Also, in the present invention according to the first aspect, the third region is a region in contact with the second semiconductor substrate surface and the fifth region, and has a higher impurity concentration than the third region. The sixth region is included.

  Further, in the present invention according to the above invention, the thyristor portion includes a seventh region that is in contact with the second region and the third region and has a breakdown voltage lower than a junction breakdown voltage between the second region and the third region. It is characterized by that.

  In the present invention, the seventh region is formed at a position where the distance from the second semiconductor substrate surface is the longest.

  According to the present invention, a semiconductor device includes a first conductivity type first region, a second conductivity type second region, a first conductivity type third region, and a second conductivity type fourth region. Are sequentially joined, and a diode part in which the second region and the third region are joined. The semiconductor device also provides a current path that flows between the first semiconductor substrate surface and the second semiconductor substrate surface during the ignition operation indicating an operation process in which the thyristor portion is conducted. A fifth region is provided that is longer than the shortest path between the surface and the second semiconductor substrate surface. The fifth region is a region formed between the first semiconductor substrate surface in contact with the second region in the diode portion and the second semiconductor substrate surface in contact with the third region in the diode portion. Thus, in the semiconductor device of the present invention, when the thyristor portion performs the ignition operation, the second region causes the second current to flow between the first semiconductor substrate surface and the second semiconductor substrate surface. A current path that flows through the third region in parallel with the semiconductor substrate surface is generated.

  Therefore, in the semiconductor device of the present invention, the current path flowing along the junction surface between the fourth region and the third region is longer than that of the semiconductor device shown in FIG. If this current path is long, a voltage drop due to the resistance component in the third region is likely to occur, so that the thyristor portion shifts to a conductive state with a breakover current smaller than that of the semiconductor device shown in FIG. Here, the ignition operation sensitivity is determined by the current path by the fifth region, and does not depend on the parameters related to the holding current characteristics and the breakdown voltage. As a result, the semiconductor device of the present invention can achieve high ignition operation sensitivity without affecting the holding current characteristics and the breakdown voltage.

It is a section lineblock diagram showing the semiconductor device in a 1st embodiment of the present invention. It is a figure which shows operation | movement of the semiconductor device in the embodiment. It is a graph which shows operation | movement of the semiconductor device in the embodiment. It is a section lineblock diagram showing a semiconductor device by a 2nd embodiment of the present invention. It is a section lineblock diagram showing a semiconductor device by a 3rd embodiment of the present invention. It is a section lineblock diagram showing a semiconductor device by a 4th embodiment of the present invention. It is a cross-sectional block diagram which shows the conventional semiconductor device.

<First Embodiment>
Hereinafter, a semiconductor device (single conduction thyristor) according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional configuration diagram illustrating a single conduction thyristor 100 according to the present embodiment.
In FIG. 1, a single conduction thyristor 100 includes a p region (1, 3, 6), an n region (2, 4, 5), a low breakdown voltage region 7, a channel stopper (8, 9), and an insulating layer (10-13). ). The single conduction thyristor 100 includes a thyristor part 110 and a diode part 120.

The thyristor part 110 functions as a thyristor by sequentially joining a p region 1 (first region), an n region 2 (second region), a p region 3 (third region), and an n region 4 (fourth region). Part.
The diode portion 120 is a portion that functions as a diode by joining the n region 2 (second region) and the p region 3 (third region).

  Note that the upper surface of the semiconductor substrate in FIG. 1 is defined as a first surface F1, and the lower surface of the semiconductor substrate is defined as a second surface F2. Of the first surface F1, the first thyristor part surface F11 is the anode surface of the thyristor part 110. Of the second surface F2, the second thyristor portion surface F21 is a cathode surface of the thyristor portion 110. Here, the anode surface of the thyristor part 110 is a semiconductor substrate surface in contact with the p region 1 in the thyristor part 110. The cathode surface of the thyristor part 110 is a semiconductor substrate surface in contact with the n region 4 in the thyristor part 110.

  Of the first surface F1, the first diode portion surface F12 (first semiconductor substrate surface) is the cathode surface of the diode portion 120. Of the second surface F2, the second diode portion surface F22 (second semiconductor substrate surface) is the anode surface of the diode portion 120. Here, the cathode surface of the diode part 120 is a semiconductor substrate surface in contact with the n region 2 in the diode part 120. The anode surface of the diode part 120 is a semiconductor substrate surface in contact with the p region 3 in the diode part 120.

  The p region 3 is a p− region of a p-type semiconductor as the first conductivity type, and constitutes a semiconductor substrate that becomes a bulk layer of the one-conductive thyristor 100. A part of the p region 3 is in contact with the second surface F2. The p region 3 is a region in contact with the second diode portion surface F22 and the n region 5, and includes a p-type semiconductor p region 6 having an impurity concentration higher than that of the p region 3.

  The n region 2 is an n + region of an n-type semiconductor as the second conductivity type. The n region 2 is formed in contact with the p region 1 and the p region 3, and a part thereof is exposed to the first surface F1. That is, in the thyristor portion 110, the n region 2 is formed in contact with the p region 1 and the p region 3. In the diode portion 120, the n region 2 is formed so as to be exposed on the first surface F1.

The p region 1 is a p ++ region of a p-type semiconductor. The p region 1 is formed in contact with the n region 2 and is exposed to the first surface F1.
The n region 4 is an n + region of an n-type semiconductor. The n region 4 is formed in contact with the p region 3 and is exposed to the second surface F2.

The n region 5 (fifth region) is an n + region of an n-type semiconductor. The n region 5 is formed between the first diode part surface F12 and the second diode part surface F22. The n region 5 is formed between the first diode portion surface F12 and the second diode portion surface F22 so as to have two junction surfaces that are in contact with the p region 3 in parallel with the second diode portion surface F22. The The n region 5 is an n + region whose region width in the direction parallel to the second diode portion surface F22 is narrower than the width of the second diode portion surface F22. Here, the width of the n region 5 (region width in a direction parallel to the second diode portion surface F22) is ΔL.
The n region 5 is formed as a part of the n region 4. That is, the n region 5 is formed continuously with the n region 4. The n region 5 has, for example, a shape obtained by extending the n region 4 to the diode part. The n region 5 is formed by forming the p region 6 together with the n region 4 by ion implantation and then forming the p region 6 by ion implantation.

  The p region 6 (sixth region) is a p + region of a p-type semiconductor having an impurity concentration higher than that of the p region 3. The p region 6 is formed in contact with the second diode portion surface F22 and the n region 5 and exposed to the first surface F1. The p region 6 is included in the p region 3 and is provided to facilitate ohmic contact with the metal terminal on the second diode portion surface F22.

  The low breakdown voltage region 7 is formed in contact with the n region 2 and the p region 3 and has a lower breakdown voltage than the junction breakdown voltage of the junction J2 between the n region 2 and the p region 3. The low withstand voltage region 7 is formed in the thyristor portion 110. The low breakdown voltage region 7 is, for example, a p ++ region of a p-type semiconductor having an impurity concentration higher than that of the p region 3. The low withstand voltage region 7 is formed, for example, by exposing it to the first surface F1 under the insulating layer 10 by ion implantation or the like. Further, the low breakdown voltage region 7 is formed such that the distance from the second diode portion surface F22 in the junction surface of the junction portion J2 is increased. A desirable arrangement position is the position where the distance from the second diode portion surface F22 is the longest or the vicinity thereof.

  The channel stopper (8, 9) is formed between the first surface F1 and the side surface of the one-side conduction thyristor 100, or in contact with the first surface F1 and between the one-side conduction thyristor 100 and its side surface, and has a p region. This is a p-type semiconductor region having an impurity concentration higher than 3. The channel stoppers (8, 9) suppress a leakage current (channel current) that is not desirable as a function of the single conduction thyristor 100.

The insulating layer 10 is formed in contact with the first surface F1. The insulating layer 10 is formed so as to cover a part of the channel stopper 8 to a part of the p region 1. The insulating layer 11 is formed in contact with the first surface F1. The insulating layer 11 is formed so as to cover a part of the channel stopper 9 to a part of the n region 2.
The insulating layer 12 is formed in contact with the second surface F2. The insulating layer 12 is formed so as to cover a part of the n region 4. The insulating layer 13 is formed in contact with the second surface F2. The insulating layer 13 is formed so as to cover a part of the p region 6.

Next, the operation of this embodiment will be described.
FIG. 2 is a diagram illustrating the operation of the single conduction thyristor 100 according to the present embodiment.
In FIG. 2, a case where a forward bias is applied between the first surface F1 and the second surface F2 will be described. Here, the case where a forward bias is applied is a case where a potential higher than the potential of the second surface F2 is applied to the first surface F1. In the first surface F1, the anode surface (first thyristor portion surface F11) of the thyristor portion 110 and the cathode surface (first diode portion surface F12) of the diode portion 120 are short-circuited. Further, on the second surface F2, the cathode surface (second thyristor portion surface F21) of the thyristor portion 110 and the anode surface (second diode portion surface F22) of the diode portion 120 are short-circuited.

In FIG. 2, a current path K <b> 1 indicates a current path that flows during an ignition operation indicating an operation process in which the thyristor unit 110 of the one-side conduction thyristor 100 is conducted.
When the forward bias as described above is applied, a reverse voltage (reverse bias) is applied to the junction J2 between the n region 2 and the p region 3. The junction breakdown voltage of the low breakdown voltage region 7 is lower than the junction breakdown voltage of the junction J2. Therefore, the low withstand voltage region 7 breaks down before the junction J2. As a result, current flows through a portion where the low breakdown voltage region 7 is joined. In the single conduction thyristor 100, the breakover voltage is a voltage obtained by adding the product of the resistance value of the current path and the breakover current value to the voltage at which the low withstand voltage region 7 breaks down.

  The current that has passed through the low withstand voltage region 7 from the cathode surface (first diode portion surface F12) of the diode portion 120 passes through the p region 3 along the junction surface of the junction portion J3 between the p region 3 and the n region 4 and thyristors. It flows in the direction from the portion 110 toward the diode portion 120. Further, this current flows through the p region 3 along the junction surface between the p region 3 and the n region 5, and reaches the anode surface (second diode portion surface F22) of the diode portion 120 via the p region 6. At this time, the n region 5 functions to lengthen the current path K1. That is, the n region 5 has a current path K1 flowing between the first diode portion surface F12 and the second diode portion surface F22 during the ignition operation indicating the operation process in which the thyristor portion 110 is conducted. It is made longer than the shortest path | route of 1 diode part surface F12 and 2nd diode part surface F22. That is, the n region 5 generates a current path parallel to the first diode part surface F12 or the second diode part surface F22 between the first diode part surface F12 and the second diode part surface F22. It is an area to be made.

  When the current passing through the current path K1 increases, the lateral resistance component in the n region 2, that is, the resistance component in the region reaching the low withstand voltage region 7 from the cathode surface of the diode portion 120 through the lower portion of the p region 1 As a result, a voltage drop occurs in the n region 2 immediately below the p region 1. Due to this voltage drop, the junction J1 between the p region 1 and the n region 2 is forward-biased. When this forward bias exceeds the diffusion potential of the junction J1, carriers are injected from the p region 1, and the bipolar transistor composed of the p region 1, the n region 2, and the p region 3 shifts to a conductive state.

  Further, when the current passing through the current path K1 increases, the p-region 3 is moved along the lateral resistance component in the p-region 3, that is, along the junction surface of the junction J3 between the p-region 3 and the n-region 4. A voltage drop occurs in the p region 3 immediately above the n region 4 due to the resistance component in the direction from 110 to the diode portion 120. Due to this voltage drop, the junction J3 between the p region 3 and the n region 4 is forward biased. When this forward bias exceeds the diffusion potential of the junction J3, carriers are injected from the n region 4, and the bipolar transistor composed of the n region 2, the p region 3, and the n region 4 shifts to a conductive state.

In the one-conductive thyristor 100, as described above, when the two bipolar transistors shift to the moving state, the thyristor section 110 shifts to the conductive state. Thus, in the one-side thyristor 100, a current flows between the anode surface (first thyristor portion surface F11) of the thyristor portion 110 and the cathode surface (second thyristor portion surface F21) of the thyristor portion 110. Here, the breakover current _IBO1 of the single conduction thyristor 100 is a current that causes the thyristor section 110 to reach the conduction state.
The value of the voltage drop in the p region 3 immediately above the n region 4 is the direction from the thyristor portion 110 toward the diode portion 120 along the junction surface of the junction portion J3 between the p region 3 and the n region 4. The larger the resistance component, the larger. That is, the value of the voltage drop increases as the current path flowing through the p region 3 in the direction from the thyristor part 110 to the diode part 120 is longer. In the single conduction thyristor 100, the current path flowing through the p region 3 in the direction from the thyristor portion 110 to the diode portion 120 is increased by the n region 5. For this reason, the single conduction thyristor 100 shifts to the conduction state with a smaller current than when the n region 5 is not provided. Therefore, the value of the breakover current I _BO1 of the single conduction thyristor 100 is reduced.

FIG. 3 is a graph showing the operation of the single conduction thyristor 100 in the present embodiment.
In FIG. 3, the graph shows the current-voltage characteristics of the single conduction thyristor 100. In addition, this graph shows a comparison of the breakover current between the conventional single conduction thyristor and the single conduction thyristor 100. In this graph, the vertical axis represents the conduction current I, and the horizontal axis represents the applied voltage V.

A waveform 101 shows a current-voltage characteristic of the single conduction thyristor 100. In waveform 101, the voltage applied to the single conducting thyristor 100 reaches the breakdown voltage V _B, the low voltage region 7, breaks down before the junction J2, the current starts to flow. When this current reaches breakover current _IBO1 , single conduction thyristor 100 shifts to a conduction state (turn-on state).
Waveform 102 shows the current-voltage characteristics of the conventional single conduction thyristor shown in FIG. 7 for comparison. In waveform 102, a current starts to flow reaches the breakdown voltage V _B reaches the breakover current I _BO2, conventional single conducting thyristor shown in Fig. 7 shifts to the conductive state (turned on).

In the graph of FIG. 3, the breakover current I _BO1 in the single conduction thyristor 100 is smaller than the breakover current I _BO2 in the conventional single conduction thyristor shown in FIG. This is because, in the single conduction thyristor 100, the length of the current path (L1 in FIG. 2) flowing through the p region 3 in the direction from the thyristor portion 110 to the diode portion 120 by the n region 5 is the same as that of the conventional single conduction thyristor. This is because the width of the n region 5 is longer by the width ΔL than the length of the current path (L2 in FIG. 7). In the single conduction thyristor 100, since the current path K1 is longer by the width ΔL of the n region 5, the value of the voltage drop is increased, and the breakover current _IBO1 can be reduced.

  As described above, the single conduction thyristor 100 causes the current path K1 flowing between the first diode portion surface F12 and the second diode portion surface F22 during the ignition operation to pass through the first diode portion surface F12. And an n region 5 that is longer than the shortest path between the second diode portion surface F22 and the second diode portion surface F22. The n region 5 is formed between the first diode portion surface F12 and the second diode portion surface F22 so as to have two junction surfaces that are in contact with the p region 3 in parallel with the second diode portion surface F22. The The n region 5 is a region where the region width in the direction parallel to the second diode portion surface F22 is narrower than the width of the second diode portion surface F22. As a result, in the single conduction thyristor 100, a current path that flows through the p region 3 in parallel with the second diode portion surface F22 is generated by the n region 5 in the current path K1.

Therefore, in single conduction thyristor 100, the current path flowing along the joint surface of joint J3 is longer than that of the conventional single conduction thyristor shown in FIG. If this current path is long, a voltage drop due to the resistance component of the p region 3 is likely to occur. Therefore, the thyristor section 110 shifts to a conductive state with a breakover current I _BO1 smaller than the conventional one-conductive thyristor shown in FIG. To do. Here, the ignition operation sensitivity indicates the magnitude of the breakover current I _BO1 that flows when the state shifts to the conductive state. The smaller the breakover current I _BO1 is, the more the ignition operation sensitivity is improved. That is, the single conduction thyristor 100 can improve the firing operation sensitivity.

Note that the ignition operation sensitivity is determined by the current path by the n region 5 and does not depend on the holding current characteristic indicating the characteristic of the thyristor and the parameter related to the breakdown voltage. As a result, the single conduction thyristor 100 can achieve high ignition operation sensitivity without affecting the holding current characteristics and the breakdown voltage.
Further, in the single conduction thyristor 100, by adjusting the width ΔL of the n region 5, the ignition operation sensitivity can be adjusted without affecting the holding current characteristic and the breakdown voltage.

<Second Embodiment>
Next, a semiconductor device (single conduction thyristor) according to a second embodiment of the present invention will be described with reference to the drawings.
FIG. 4 is a cross-sectional configuration diagram illustrating the single conduction thyristor 100a according to the present embodiment.
In FIG. 4, the single conduction thyristor 100a includes a p region (1, 3, 6), an n region (2, 4, 5), a low breakdown voltage region 7a, a channel stopper (8, 9), and an insulating layer (10-13). ). In this figure, the same components as those in FIG.

  The low breakdown voltage region 7 a is formed in contact with the n region 2 and the p region 3, and has a lower breakdown voltage than the junction breakdown voltage of the junction J <b> 2 between the n region 2 and the p region 3. The low withstand voltage region 7 a is, for example, a p ++ region of a p-type semiconductor having an impurity concentration higher than that of the p region 3. The low withstand voltage region 7a is formed in the thyristor portion 110, and is formed on a joint surface parallel to the first surface F1 or the second surface F2 in the joint portion J2. The low withstand voltage region 7a is formed by being embedded in the semiconductor substrate by, for example, a buried diffusion method.

Next, the operation of this embodiment will be described.
The single conduction thyristor 100a shown in FIG. 4 operates similarly except that the low breakdown voltage region 7 of the single conduction thyristor 100 is replaced with the low breakdown voltage region 7a.
In FIG. 4, a case where a forward bias is applied between the first surface F1 and the second surface F2 will be described. Here, the case where a forward bias is applied is a case where a potential higher than the potential of the second surface F2 is applied to the first surface F1. In this figure, a current path K2 indicates a current path that flows during an ignition operation indicating an operation process in which the thyristor portion 110 of the one-side conduction thyristor 100a conducts.
When the forward bias as described above is applied, a reverse voltage (reverse bias) is applied to the junction J2 between the n region 2 and the p region 3. The junction breakdown voltage of the low breakdown voltage region 7a is lower than the junction breakdown voltage of the junction J2. Therefore, the low withstand voltage region 7a breaks down before the junction J2. As a result, current flows through the portion where the low breakdown voltage region 7a is joined. In the single conduction thyristor 100a, the breakover voltage is a voltage obtained by adding the product of the resistance value of the current path and the breakover current value to the voltage at which the low withstand voltage region 7a breaks down.

  The current that has passed through the low withstand voltage region 7a from the cathode surface (first diode portion surface F12) of the diode portion 120 passes through the p region 3 along the junction surface of the junction region J3 between the p region 3 and the n region 4 and then thyristors. It flows in the direction from the portion 110 toward the diode portion 120. Further, this current flows through the p region 3 along the junction surface between the p region 3 and the n region 5, and reaches the anode surface (second diode portion surface F22) of the diode portion 120 via the p region 6. At this time, the n region 5 functions to lengthen the current path K2. That is, the n region 5 has a first current path flowing between the first diode portion surface F12 and the second diode portion surface F22 during the ignition operation indicating the operation process in which the thyristor portion 110 is conducted. Longer than the shortest path between the diode part surface F12 and the second diode part surface F22.

  When the current passing through the current path K2 increases, the state transitions to a conducting state, similar to the operation of the one-sided thyristor 100 in the first embodiment. That is, the bipolar transistor composed of the p region 1, the n region 2, and the p region 3 and the bipolar transistor composed of the n region 2, the p region 3, and the n region 4 shift to a conductive state.

In the single conduction thyristor 100a, as described above, when the two bipolar transistors are shifted to the active state, the thyristor section 110 is shifted to the conductive state. Thus, in the one-side thyristor 100a, a current flows between the anode surface of the thyristor part 110 (first thyristor part surface F11) and the cathode surface of the thyristor part 110 (second thyristor part surface F21). Here, the breakover current _IBO1 of the one-sided thyristor 100a is a current at which the thyristor unit 110 reaches the conduction state.

  As described above, the single conduction thyristor 100a causes the current path K2 flowing between the first diode portion surface F12 and the second diode portion surface F22 during the ignition operation to pass through the first diode portion surface F12. And an n region 5 that is longer than the shortest path between the second diode portion surface F22 and the second diode portion surface F22. The n region 5 is formed between the first diode portion surface F12 and the second diode portion surface F22 so as to have two junction surfaces that are in contact with the p region 3 in parallel with the second diode portion surface F22. The The n region 5 is a region where the region width in the direction parallel to the second diode portion surface F22 is narrower than the width of the second diode portion surface F22. Thereby, in the single conduction thyristor 100a, a current path that flows through the p region 3 in parallel with the second diode portion surface F22 is generated by the n region 5 in the current path K2.

Therefore, in single conduction thyristor 100a, the current path flowing along the joint surface of junction J3 is longer than that of a conventional single conduction thyristor that does not include n region 5. Therefore, the single conduction thyristor 100a transitions to the conduction state at a breakover current _IBO1 lower than that of the conventional single conduction thyristor that does not include the n region 5, similarly to the single conduction thyristor 100 in the first embodiment. That is, the single conduction thyristor 100a can improve the ignition operation sensitivity. As a result, the single conduction thyristor 100a can achieve a high ignition operation sensitivity without affecting the holding current characteristics and the breakdown voltage.

<Third Embodiment>
Next, a semiconductor device (single conduction thyristor) according to a third embodiment of the present invention will be described with reference to the drawings.
FIG. 5 is a cross-sectional configuration diagram illustrating the single conduction thyristor 100b according to the present embodiment.
In FIG. 5, the single conduction thyristor 100b includes a p region (1, 3, 6), an n region (2, 4, 5), a low breakdown voltage region 7b, a channel stopper (8, 9), and an insulating layer (10-13). ). In this figure, the same components as those in FIG.

  The low breakdown voltage region 7 b is formed in contact with the n region 2 and the p region 3, and has a lower breakdown voltage than the junction breakdown voltage of the junction J <b> 2 between the n region 2 and the p region 3. The low breakdown voltage region 7b is a p ++ region of a p-type semiconductor having an impurity concentration higher than that of the p region 3, for example. Further, the low withstand voltage region 7b is formed in the thyristor portion 110, and is formed on a joint surface parallel to the first surface F1 or the second surface F2 in the joint portion J2. The low withstand voltage region 7b is formed by being embedded in the semiconductor substrate by, for example, a buried diffusion method. Further, the low breakdown voltage region 7b is formed such that the distance from the second diode portion surface F22 in the junction surface of the junction portion J2 is increased. A desirable arrangement position is the position where the distance from the second diode portion surface F22 is the longest or the vicinity thereof. The low breakdown voltage region 7b has a longer distance from the second diode portion surface F22 than the low breakdown voltage region 7a of the second embodiment in FIG.

Next, the operation of this embodiment will be described.
The single conduction thyristor 100b shown in FIG. 5 operates similarly except that the low breakdown voltage region 7 of the single conduction thyristor 100a is replaced with the low breakdown voltage region 7b.
In FIG. 5, a case where a forward bias is applied between the first surface F1 and the second surface F2 will be described. Here, the case where a forward bias is applied is a case where a potential higher than the potential of the second surface F2 is applied to the first surface F1. In this figure, a current path K3 indicates a current path that flows during an ignition operation indicating an operation process in which the thyristor portion 110 of the one-side conduction thyristor 100b conducts.
When the forward bias as described above is applied, a reverse voltage (reverse bias) is applied to the junction J2 between the n region 2 and the p region 3. The junction breakdown voltage of the low breakdown voltage region 7b is lower than the junction breakdown voltage of the junction J2. Therefore, the low withstand voltage region 7b breaks down before the junction J2. As a result, current flows through a portion where the low breakdown voltage region 7b is joined. In the single conduction thyristor 100b, the breakover voltage is a voltage obtained by adding the product of the resistance value of the current path and the breakover current value to the voltage at which the low withstand voltage region 7b breaks down.

  The current that has passed through the low withstand voltage region 7a from the cathode surface (first diode portion surface F12) of the diode portion 120 passes through the p region 3 along the junction surface of the junction region J3 between the p region 3 and the n region 4 and then thyristors. It flows in the direction from the portion 110 toward the diode portion 120. Further, this current flows through the p region 3 along the junction surface between the p region 3 and the n region 5, and reaches the anode surface (second diode portion surface F22) of the diode portion 120 via the p region 6. At this time, the n region 5 functions to lengthen the current path K3. Further, since the low withstand voltage region 7b is formed at a position where the distance from the second diode portion surface F22 is the longest, the current path K3 is more than the current path K2 in the one-side thyristor 100a of the second embodiment. become longer.

  When the current passing through the current path K3 increases, the state shifts to the conductive state, similarly to the operation of the one-side thyristor 100 in the first embodiment. That is, the bipolar transistor composed of the p region 1, the n region 2, and the p region 3 and the bipolar transistor composed of the n region 2, the p region 3, and the n region 4 shift to a conductive state.

In the single conduction thyristor 100b, as described above, the two bipolar transistors shift to the moving state, so that the thyristor section 110 shifts to the conductive state. As a result, in the single conduction thyristor 100b, the thyristor part 110 shifts to the conduction state, and the anode surface of the thyristor part 110 (first thyristor part surface F11) and the cathode surface of the thyristor part 110 (second thyristor part surface F21). Current flows between them. Here, the breakover current _IBO1 of the single conduction thyristor 100b is a current that reaches the conduction state of the thyristor section 110.

  As described above, the single conduction thyristor 100b causes the current path K3 flowing between the first diode portion surface F12 and the second diode portion surface F22 during the ignition operation to pass through the first diode portion surface F12. And an n region 5 that is longer than the shortest path between the second diode portion surface F22 and the second diode portion surface F22. The n region 5 is formed between the first diode portion surface F12 and the second diode portion surface F22 so as to have two junction surfaces that are in contact with the p region 3 in parallel with the second diode portion surface F22. The The n region 5 is a region where the region width in the direction parallel to the second diode portion surface F22 is narrower than the width of the second diode portion surface F22. Further, the low breakdown voltage region 7b is formed at a position where the distance from the second diode portion surface F22 is the longest. Thereby, in the single conduction thyristor 100b, the current path flowing in the p region 3 in parallel with the second diode portion surface F22 is arranged in the current path K3 by the arrangement of the n region 5 and the low breakdown voltage region 7b in the second embodiment. Longer than the similar current path in the single conduction thyristor 100a.

Therefore, in the single conduction thyristor 100b, the current path flowing along the joint surface of the joint portion J3 is longer than that of the conventional single conduction thyristor shown in FIG. 7 and the single conduction thyristor 100a of the second embodiment. Therefore, the single conduction thyristor 100b transitions to the conduction state at a breakover current _IBO1 lower than that of the conventional single conduction thyristor shown in FIG. 7, similarly to the single conduction thyristor 100 in the first embodiment. Furthermore, the single conduction thyristor 100b shifts to the conduction state with a breakover current _IBO1 lower than that of the single conduction thyristor 100a of the second embodiment. That is, the single conduction thyristor 100b can further improve the firing operation sensitivity than the single conduction thyristor 100a of the second embodiment. As a result, the single conduction thyristor 100b can achieve high ignition operation sensitivity without affecting the holding current characteristics and the breakdown voltage.

<Fourth Embodiment>
Next, a semiconductor device (single conduction thyristor) according to a fourth embodiment of the present invention will be described with reference to the drawings.
FIG. 6 is a cross-sectional configuration diagram showing the one-sided thyristor 100c according to the present embodiment.
In FIG. 6, the single conducting thyristor 100 c includes a p region (1, 3), an n region (2, 4, 5, 6), a channel stopper (8, 9), and an insulating layer (10-13). In this figure, the same components as those in FIG. The single conduction thyristor 100c has a configuration that does not include a low breakdown voltage region.

Next, the operation of this embodiment will be described.
The single conduction thyristor 100c shown in FIG. 6 operates similarly except that the low breakdown voltage region 7 of the single conduction thyristor 100 is not provided.
In FIG. 6, a case where a forward bias is applied between the first surface F1 and the second surface F2 will be described. Here, the case where a forward bias is applied is a case where a potential higher than the potential of the second surface F2 is applied to the first surface F1. In this figure, a current path K4 shows an example of a current path that flows during an ignition operation indicating an operation process in which the thyristor section 110 of the one-side conduction thyristor 100c conducts.
When the forward bias as described above is applied, a reverse voltage (reverse bias) is applied to the junction J2 between the n region 2 and the p region 3. When this reverse voltage reaches the junction withstand voltage of the junction J2, the portion with the lowest junction withstand voltage of the junction J2 breaks down. As a result, a current flows through the broken junction.
Further, since the single conduction thyristor 100c does not have a low breakdown voltage region, breakdown may occur at any position of the junction J2 between the n region 2 and the p region 3. In the present embodiment, an example in which breakdown occurs in the diode unit 120 is shown.

  The current that has passed through the junction portion broken down from the cathode surface (first diode portion surface F12) of the diode portion 120 is along the junction surface of the junction portion J3 between the p region 3 and the n region 4 (n region 5). , P region 3 flows in a direction from thyristor portion 110 toward diode portion 120. Further, this current reaches the anode surface (second diode portion surface F22) of the diode portion 120 via the p region 6. At this time, the n region 5 functions to lengthen the current path K4.

  When the current passing through the current path K4 increases, the lateral resistance component in the p region 3, that is, the p region 3 along the junction surface of the junction J3 between the p region 3 and the n region 4 (n region 5). Due to the resistance component in the direction from the thyristor part 110 to the diode part 120, a voltage drop occurs in the p region 3 immediately above the n region 4 and the n region 5. Due to this voltage drop, the junction J3 between the p region 3, the n region 4, and the n region 5 is forward-biased. When this forward bias exceeds the diffusion potential of the junction J3, carriers are injected from the n region 4, and the bipolar transistor composed of the n region 2, the p region 3, and the n region 4 shifts to a conductive state.

  Further, when the current flowing from the cathode surface of the diode unit 120 to the anode surface of the diode unit 120 increases, a current path is generated from the cathode surface of the diode unit 120 through the n region 2 below the p region 1. As a result, a voltage drop occurs in the n region 2 immediately below the p region 1 due to the lateral resistance component in the n region 2, that is, the resistance component of the n region 2 portion below the p region 1 from the cathode surface of the diode portion 120. . Due to this voltage drop, the junction J1 between the p region 1 and the n region 2 is forward-biased. When this forward bias exceeds the diffusion potential of the junction J1, carriers are injected from the p region 1, and the bipolar transistor composed of the p region 1, the n region 2, and the p region 3 shifts to a conductive state.

In the one-conductive thyristor 100c, as described above, when the two bipolar transistors are shifted to the active state, the thyristor section 110 is shifted to the conductive state. Thus, in the one-side thyristor 100a, a current flows between the anode surface of the thyristor part 110 (first thyristor part surface F11) and the cathode surface of the thyristor part 110 (second thyristor part surface F21). Here, the breakover current _IBO1 of the single conduction thyristor 100c is a current that causes the thyristor section 110 to reach the conduction state.

  As described above, the single conduction thyristor 100c causes the current path K4 flowing between the first diode portion surface F12 and the second diode portion surface F22 during the ignition operation to pass through the first diode portion surface F12. And an n region 5 that is longer than the shortest path between the second diode portion surface F22 and the second diode portion surface F22. The n region 5 is formed between the first diode portion surface F12 and the second diode portion surface F22 so as to have two junction surfaces that are in contact with the p region 3 in parallel with the second diode portion surface F22. The The n region 5 is a region where the region width in the direction parallel to the second diode portion surface F22 is narrower than the width of the second diode portion surface F22. Thereby, in the single conduction thyristor 100c, a current path that flows in the p region 3 in parallel with the second diode portion surface F22 is generated by the n region 5 in the current path K4.

Therefore, in the single conduction thyristor 100c, the current path flowing along the joint surface of the joint portion J3 is longer than in the conventional single conduction thyristor without the n region 5. Therefore, the single conduction thyristor 100c can improve the ignition operation sensitivity, similarly to the single conduction thyristor 100 in the first embodiment. Thereby, the single conduction thyristor 100c can realize high ignition operation sensitivity without affecting the holding current characteristic and the breakdown voltage.
Further, the single conduction thyristor 100c does not include a low breakdown voltage region. In this case, the breakdown voltage of the single conduction thyristor is determined by the junction breakdown voltage of the junction J2. For this reason, in the single conduction thyristor 100c, the breakdown voltage can be increased.

According to the embodiment of the present invention, the single conduction thyristor 100, 100a, 100b, or 100c (semiconductor device) includes the p region 1 (first region) and the n type of the p type semiconductor (first conductivity type). Thyristor in which an n region 2 (second region) of a semiconductor (second conductivity type), a p region 3 (third region) of a p type semiconductor, and an n region 4 (fourth region) of an n type semiconductor are joined in order. Part 110 and diode part 120 in which n region 2 and p region 3 are joined. The single conduction thyristor 100, 100 a, 100 b, or 100 c includes a second diode surface 120 that contacts the n region 2 in the diode portion 120 (first semiconductor substrate surface) and a second region that contacts the p region 3 in the diode portion 120. The first diode portion surface F12 and the second diode portion surface are formed between the diode portion surface F22 (second semiconductor substrate surface) and in the ignition operation indicating the operation process in which the thyristor portion 110 conducts. An n region 5 (fifth region) is provided in which a current path flowing between the first diode part surface F12 and the second diode part surface F22 is made longer than a shortest path between the first diode part surface F12 and the second diode part surface F22.
As a result, the single conduction thyristor 100, 100a, 100b, or 100c can realize high ignition operation sensitivity without affecting the holding current characteristics and the breakdown voltage.

Further, the n region 5 includes two junction surfaces that are in contact with the p region 3 in parallel with the second diode portion surface F22 between the first diode portion surface F12 and the second diode portion surface F22. An n-type semiconductor region formed and having a region width in a direction parallel to the second diode portion surface F22 smaller than the width of the second diode portion surface F22 is formed as a part of the n region 4. .
Thereby, the current path which flows along the junction surface of junction J3 can be made longer than the conventional one conduction thyristor which is not provided with n field 5. Therefore, the single conduction thyristor 100, 100a, 100b, or 100c can achieve high ignition operation sensitivity without affecting the holding current characteristics and the breakdown voltage.

The p region 3 is a region in contact with the second diode portion surface F22 and the n region 5, and includes a p-type semiconductor p region 6 (sixth region) having a higher impurity concentration than the p region 3.
The higher the impurity concentration, the easier the ohmic contact is made. Therefore, when a metal terminal is formed on the second diode portion surface F22, an effect that the ohmic contact becomes easy can be expected. In addition, the n region 4 is formed by exposing the second region F2 to the second surface F2 by ion implantation or the like, and then the p region 6 is exposed to the surface F2 by ion implantation or the like. Can be simplified.

The thyristor section 110 includes a low breakdown voltage region 7, 7 a or 7 b (seventh region) that is in contact with the n region 2 and the p region 3 and has a breakdown voltage lower than the junction breakdown voltage between the n region 2 and the p region 3.
Thereby, the single conduction thyristor 100, 100a, or 100b can reduce the breakdown voltage.

The low breakdown voltage region 7 or 7b is formed at a position where the distance from the second diode portion surface F22 is the longest.
Thereby, the electric current path which flows along the junction surface of junction part J3 can be made still longer. Therefore, the single conduction thyristor 100 or 100b can further improve the high sensitivity of the firing operation sensitivity.

  The present invention is not limited to the above embodiments, and can be modified without departing from the spirit of the present invention. In each of the above embodiments, the first conductivity type has been described as a p-type semiconductor, and the second conductivity type has been described as an n-type semiconductor. However, the first conductivity type is an n-type semiconductor, and the second conductivity type is a p-type semiconductor. It is good. In this case, conduction is made in the direction from the fourth region (p-type semiconductor region) to the first region (n-type semiconductor region), and the conduction direction is the reverse of the above embodiments.

Further, in each of the above-described embodiments, the mode including the channel stopper (8, 9) has been described. However, the present invention may be applied to a mode not including the channel stopper (8, 9).
Further, in each of the above embodiments, the second diode portion surface F22 (second semiconductor substrate surface) indicates the semiconductor substrate surface in contact with the p region 3 (p region 6) in the diode portion 120, and the insulating layer 13 Although the form including the covered portion has been described, a form not including the portion covered with the insulating layer 13 may be used.

In each of the above embodiments, the single conduction thyristor 100, 100 a, 100 b, or 100 c has been described as having the p region 6. In this case, the n region 5 is formed by being buried in the semiconductor substrate by, for example, a buried diffusion method, and the process of forming the p region 6 can be reduced.
In the first to third embodiments, the low breakdown voltage region 7, 7 a or 7 b has been described as a p ++ region of a p-type semiconductor having a higher impurity concentration than the p region 3. However, the present invention is not limited to this. It is not something. For example, the low breakdown voltage region may be formed of an n ++ region of an n-type semiconductor having an impurity concentration higher than that of the n region 2, or may be any other form as long as the breakdown voltage is lower than the junction breakdown voltage of the junction J2.

1, 3, 6 p region 2, 4, 5 n region 7, 7a, 7b Low breakdown voltage region 8, 9 Channel stopper 10, 11, 12, 13 Insulating layer 100, 100a, 100b, 100c Single conducting thyristor 110 Thyristor portion 120 Diode part

Claims (5)

A thyristor portion in which a first region of a first conductivity type, a second region of a second conductivity type, a third region of the first conductivity type, and a fourth region of the second conductivity type are sequentially joined; , have a said second region and the third region and the junction diodes portion, the third region in the first semiconductor substrate surface and the diode portion of the portion in contact with the second region in the diode unit A semiconductor device that is a one-sided thyristor disposed so as to face a second semiconductor substrate surface of a portion in contact with the semiconductor device,
Formed between the first semiconductor substrate surface and the front Symbol both opposite the first semiconductor substrate surface and the second semiconductor substrate surface of the second semiconductor substrate surface, wherein the thyristor is conducting A current path that flows between the first semiconductor substrate surface and the second semiconductor substrate surface during an ignition operation that indicates an operation process of the first semiconductor substrate surface and the second semiconductor substrate A semiconductor device, comprising: a fifth region that is longer than the shortest path to the surface. The fifth region is
Between the first semiconductor substrate surface and the second semiconductor substrate surface, two bonding surfaces that are in contact with the third region in parallel with the second semiconductor substrate surface are formed, and the second semiconductor substrate surface is formed. The region width in the direction parallel to the semiconductor substrate surface is a region of the second conductivity type that is narrower than the width of the second semiconductor substrate surface, and is formed as a part of the fourth region. The semiconductor device according to claim 1. The third region is
The region in contact with the second semiconductor substrate surface and the fifth region includes the sixth region of the first conductivity type having an impurity concentration higher than that of the third region. Item 3. The semiconductor device according to Item 2. The thyristor section is
The seventh region according to any one of claims 1 to 3, further comprising a seventh region in contact with the second region and the third region and having a breakdown voltage lower than a junction breakdown voltage between the second region and the third region. 2. A semiconductor device according to item 1. The seventh region is
The semiconductor device according to claim 4, wherein the semiconductor device is formed at a position where a distance from the second semiconductor substrate surface is longest.

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