JP2017163109A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device which enables improvement of heat radiation performance without increasing the size.SOLUTION: A semiconductor device includes: a semiconductor substrate 10; a gate electrode 12 formed on the semiconductor substrate 10; a source electrode 11 and a drain electrode 13 which are formed on the semiconductor substrate 10 while being separated from the gate electrode 12 and sandwiching the gate electrode 12 therebetween; an insulator layer 14 which coats areas on the semiconductor substrate 10 which are located among the gate electrode 12, the source electrode 11, and the drain electrode 13 and an area on the gate electrode 12; a source field plate electrode 15 formed on an area on the insulator layer 14, which is located closer to the drain electrode 13 side than at least the gate electrode 12, and electrically connected with the source electrode 11; and a heat radiation member 16 which is formed on the source field plate electrode 15 and radiates heat generated near the gate electrode to the outside of a semiconductor.SELECTED DRAWING: Figure 3

Description

  Embodiments described herein relate generally to a semiconductor device.

  As a high-power semiconductor device used for a communication device or the like, there is a nitride semiconductor using gallium nitride (GaN). The semiconductor device for high power includes a HEMT structure semiconductor device in which a gallium nitride layer (GaN layer) is formed and an aluminum gallium nitride layer (AlGaN layer) containing aluminum element (Al) is formed thereon. Are known.

  However, a semiconductor device using a nitride semiconductor has a problem that when a large amount of power is applied, heat generation under the gate electrode becomes remarkable, and the characteristics of the semiconductor device are deteriorated. In the prior art, a semiconductor device is known in which a hollow heat dissipation path is formed between each of the source electrode, the gate electrode, and the drain electrode, and one end of the heat dissipation path is connected to a heat dissipation pad formed outside the semiconductor operating region. However, since the heat dissipating pad is provided, there is a problem that the size of the semiconductor device is increased.

JP 2008-112793 A

  The problem to be solved by the present invention is to provide a semiconductor device having improved heat dissipation characteristics without increasing the size.

  In order to solve the above problems, a semiconductor device according to an embodiment is formed on a semiconductor substrate, a gate electrode formed on the semiconductor substrate, and on the semiconductor substrate, spaced apart from the gate electrode and sandwiching the gate electrode. A source electrode and a drain electrode; an insulator layer covering the semiconductor substrate and the gate electrode between the gate electrode, the source electrode and the drain electrode; and the insulator at least on the drain electrode side of the gate electrode A source field plate electrode formed on the layer and electrically connected to the source electrode; and a heat dissipation member formed on the source field plate electrode and dissipating heat generated near the gate electrode to the outside of the semiconductor; Are provided.

The top view of the semiconductor device of a 1st embodiment. 1 is a perspective view of a semiconductor device according to a first embodiment. Sectional drawing of the semiconductor device of 1st Embodiment. Sectional drawing of the semiconductor device of 2nd Embodiment. Sectional drawing of the semiconductor device of 3rd Embodiment. The perspective view of the semiconductor device of a 4th embodiment. The perspective view of the semiconductor device of a 5th embodiment.

  Embodiments for carrying out the invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a plan view of the first embodiment, and FIG. 2 is a perspective view of the first embodiment. FIG. 3 is a cross-sectional view taken along the dotted line AA ′ in FIGS. 1 and 2.

  In the semiconductor device 101 of this embodiment, a source electrode 11, a gate electrode 12 (broken line portion), and a drain electrode 13 are formed on a semiconductor substrate 10. The gate electrode 12 is connected to the gate electrode of an adjacent transistor through a connection portion 12a. The connecting portion 12a is connected to a gate pad 12b formed on the semiconductor substrate 10. Thereby, a voltage is simultaneously applied to the gate electrodes 12 of two adjacent transistors by applying a voltage to the gate pad 12b.

  1 and 2 form two transistors, and the drain electrode 13 is a common electrode. The source electrode 11 is connected to the source electrode 11 of the adjacent transistor. In FIGS. 1 and 2, the region corresponding to two transistors sharing the drain electrode 13 is described. However, when the transistors are further adjacent, the source electrode 11 and the drain electrode are shared with the adjacent transistors.

  The gate electrode 12 is formed on the semiconductor substrate 10 so as to be sandwiched between the source electrode 11 and the drain electrode 13. Since the insulator layer 14 is formed on the gate electrode 12, the gate electrode 12 is covered with the insulator layer 14 in FIG. 1 and FIG.

  The insulator layer 14 covers the semiconductor substrate 10 between the gate electrode 12 and the source electrode 11, the semiconductor substrate 10 between the gate electrode 12 and the drain electrode 13, and the gate electrode 12.

  Examples of the material of the insulator layer 14 include silicon nitride (SiN) and silicon oxide (SiO 2). However, the material of the insulator layer 14 is not limited to these.

  In the present embodiment, the source field plate electrode 15 is formed on the insulator layer 14 on the drain electrode 13 side of the gate electrode 12, and the source field plate electrode 15 is electrically connected to the source electrode 11 through the connection portion 17. Connected. On the source field plate electrode 15, heat radiating fins (hereinafter referred to as heat radiating members 16) are formed.

  Next, description will be made with reference to the cross-sectional view of FIG.

  A gate electrode 12 and a source electrode 11 and a drain electrode 13 are formed on the semiconductor substrate 10 so as to be spaced apart from each other with the gate electrode 12 interposed therebetween.

  The insulator layer 14 covers the semiconductor substrate 10 between the gate electrode 12 and each electrode. In this embodiment, the insulating layer 14 covers a part on the source electrode 11 and the drain electrode 13, but the coating ratio is not limited to FIG. 3.

  In this embodiment, a source field plate electrode 15 is formed on at least the insulator layer 14 closer to the drain electrode 13 than the gate electrode 12. By forming the source field plate electrode 15 on the insulator layer 14 closer to the drain electrode 13 than the gate electrode 12, the peak value of the electric field intensity generated under the gate electrode 12 can be lowered and heat generation can be suppressed. .

  In this embodiment, the source field plate electrode 15 is formed to extend on the insulator layer 14 on the drain electrode 13 side of the gate electrode 12 and further on the insulator layer 14 formed on the gate electrode 12. ing.

  On the upper part of the source electrode 11 and the drain electrode 13, wiring platings 11a and 13a are formed by wire bonding, respectively. The platings 11a and 13a are electrically connected to the source electrode 11 and the drain electrode 13, respectively. In the present embodiment, the source field plate electrode 15 and the source electrode 11 are electrically connected via the connection portion 17 and the plating 11a. However, the connection portion 17 is directly connected to the source electrode 11 not via the plating 11a. May be.

  On the source field plate electrode 15, a heat radiating member 16 that radiates heat generated near the gate electrode 12 to the outside of the semiconductor is formed. In order to improve heat dissipation, at least a part of the heat dissipation member 16 is exposed to the air.

  If the width of the heat dissipation member 16 in the direction between the gate electrode 12 and the drain electrode 13 is a width W, the heat dissipation member 16 extends in a direction orthogonal to the semiconductor substrate 10 and is above the source field plate electrode 15. The portion has a substantially uniform width W along the extending direction.

  The heat dissipating member 16 is made of the same material as that of the source field plate electrode 15, so that the heat conducted from the gate electrode 12 can be radiated more easily than the source field plate electrode 15 alone. Further, the heat dissipation member 16 may be made of a metal having a higher thermal conductivity than the source field plate electrode 15 to improve heat dissipation. For example, the source field plate electrode 15 is made of an alloy of titanium (Ti) and aluminum (Al). Therefore, the heat dissipation can be enhanced by forming the source field plate electrode 15 with gold (Au), copper (Cu), or an alloy thereof having a higher thermal conductivity than the alloy.

  In addition, as a method for forming the heat radiating member 16, a resist is applied to a region other than a portion where the heat radiating member 16 is formed, and then formed by a vacuum deposition method. Thereafter, the heat radiating member 16 can be formed by removing the resist. The same applies to the following embodiments. However, the method of forming the heat radiating member 16 is not limited to the vacuum vapor deposition method.

  By configuring as described above, the present embodiment can improve the heat dissipation characteristics without increasing the size.

(Second Embodiment)
FIG. 4 is a cross-sectional view of the semiconductor device 102 of the second embodiment. The difference between the present embodiment and the first embodiment is that the source field plate electrode 15a is formed on the insulator layer 14 on the drain electrode 13 side of the gate electrode 12, and the insulator formed on the gate electrode 12 It is not formed on the layer 14.

  Moreover, the heat radiating member 16 extends in a direction orthogonal to the semiconductor substrate 10, and the width W is substantially uniform along the extending direction as a whole.

  In the case of this embodiment, the surface area exposed to the air of the heat radiating member 16 becomes larger than that of the first embodiment, and the effect of further improving the heat dissipation characteristics is obtained.

  The material of the heat radiating member 16 is the same as that of the source field plate electrode 15a as in the first embodiment, or the heat dissipation is improved by using a metal having higher thermal conductivity than the source field plate electrode 15a. Can do.

  By configuring as described above, the present embodiment can improve the heat dissipation characteristics without increasing the size.

(Third embodiment)
5A and 5B are cross-sectional views of the semiconductor device 103 according to the third embodiment. The difference between the present embodiment and the first embodiment is that the heat dissipation member 16 extends in a direction orthogonal to the semiconductor substrate 10, and the width W decreases (FIG. 5A) or increases (FIG. b)) is to do.

  The width W of the heat dissipating member 16 (16a) in FIG. 5 decreases in the extending direction. The width W of the heat dissipating member 16 (16b) in FIG. 6 increases in the extending direction.

  In the case of the present embodiment, the surface area exposed in the air is increased by reducing or increasing the width W of the heat radiating member 16 along the extending direction as compared with the substantially uniform shape. This has the effect of improving the heat dissipation characteristics.

  The material of the heat radiating member 16 (16a, 16b) is the same material as the source field plate electrode 15 as in the first embodiment, or a metal having higher thermal conductivity than the source field plate electrode 15 is used. Heat dissipation can be improved.

  The source field plate electrode 15 of the present embodiment is formed by extending on the insulator layer 14 on the drain electrode 13 side of the gate electrode 12 and further on the insulator layer 14 formed on the gate electrode 12. However, it may not be formed on the insulator layer 14 formed on the gate electrode 12. That is, the same shape as the source field plate electrode 15a of the second embodiment may be used.

  By configuring as described above, the present embodiment can improve the heat dissipation characteristics without increasing the size.

(Fourth embodiment)
FIG. 6 is a perspective view of the semiconductor device 104 of the fourth embodiment. In FIG. 6, two transistors are formed. The semiconductor device 104 according to the fourth embodiment includes a first gate electrode 121 and a first source formed on the semiconductor substrate 10 with the first gate electrode 121 sandwiched between the first gate electrode 121 and the first gate electrode 121. An electrode 111 and a drain electrode 13 are formed. In addition, a second gate electrode 122 provided apart from the drain electrode 13 and a second source electrode 112 formed apart from the second gate electrode 122 are formed. Further, similarly to FIG. 1, the connection portion 12a and the gate pad 12b are provided, and a voltage is applied simultaneously to the first gate electrode 121 and the second gate electrode 122 by applying a voltage to the gate pad 12b. The drain electrode 13 is a common electrode.

  Since the insulator layer 14 is formed on the first gate electrode 121 and the second gate electrode 122, the first gate electrode 121 and the second gate electrode 122 are formed on the insulator layer 14 in FIG. It is in a covered state (indicated by a broken line).

  The insulator layer 14 is formed on the semiconductor substrate 10 between the first gate electrode 121, the first source electrode 111 and the drain electrode 13, and between the second gate electrode 122, the second source electrode 112 and the drain electrode 13. The substrate 10, the first gate electrode 121, and the second gate electrode 122 are covered.

  In the present embodiment, the first source field plate electrode 151 is formed on at least the insulator layer closer to the drain electrode 13 than the first gate electrode 121, and is connected to the first source electrode 111 via the connection portion 171. Electrically connected.

  The second source field plate electrode 152 is formed on at least the insulator layer closer to the drain electrode 13 than the second gate electrode 122, and is electrically connected to the second source electrode 112 through the connection portion 172. It is connected to the.

  In the present embodiment, as in the first embodiment, the first source field plate electrode 151 may be further formed to extend on the insulating layer 14 on the first gate electrode 121, and the second source The field plate electrode 152 may further be formed to extend on the insulating layer 14 on the second gate electrode 122.

  A first radiating fin (first radiating member 161 (161c)) is formed on the first source field plate electrode 151 to radiate heat generated in the vicinity of the first gate electrode 121 to the outside of the semiconductor. In addition, a second radiating fin (second radiating member 162 (162c)) is formed on the second source field plate electrode 152, and radiates heat generated near the second gate electrode 122 to the outside of the semiconductor. To do. Therefore, at least a part of the first heat radiating member 161 (161c) and the second heat radiating member 162 (162c) is exposed to the air.

  In the embodiment, the first heat radiating member 161 (161c) and the second heat radiating member 162 (162c) are provided to face each other. Further, the first heat radiation member 161 (161c) and the second heat radiation member 162 (162c) have different heights along the longitudinal direction of the first source field plate electrode 151 and the second source field plate electrode 152. doing.

  The thick arrow in FIG. 6 represents the direction of air convection. When the first heat radiating member 161 (161c) and the second heat radiating member 162 (162c) are not uneven with different heights, the first source field plate electrode 151 and the second source field plate electrode 152 are arranged in the longitudinal direction. Only air convection is generated, but the first heat radiating member 161 (161c) and the second heat radiating member 162 (162c) are provided with irregularities having different heights as shown in FIG. It passes through the recesses of the member 161 (161c) and the second heat radiation member 162 (162c). That is, air convection also occurs in the direction of the first and second source electrodes 111 and 112 and the drain electrode 13. For this reason, the convection of the atmosphere in the air is improved, and the heat dissipation characteristics can be improved without increasing the size of the semiconductor device.

(Fifth embodiment)
FIG. 7 is a perspective view of the semiconductor device 105 of the fifth embodiment. The difference between the present embodiment and the fourth embodiment is that the first heat radiating member 161 (161d) and the second heat radiating member 162 (162d) provided opposite to each other are the first source field plate electrode 151 and The second source field plate electrode 152 is formed such that opposing portions along the longitudinal direction are formed at different heights.

  A thick arrow in FIG. 7 represents the direction of air convection. As shown in FIG. 7, the first heat radiating member 161 (161d) and the second heat radiating member 162 (162d) have different heights along the longitudinal direction. In the present embodiment, the first heat radiation member 161 (161d) is provided higher on the gate electrode pad 12b side, and the second heat radiation member 162 (162d) is provided lower on the gate electrode pad 12b side.

  In the case of such a structure, air convection from the low height portion of the first source electrode 111 to the drain electrode 13 is possible, and air is allowed to flow from the low height portion of the second source electrode 112 to the drain electrode 13. Convection is possible. Air convection is generated from regions where the first heat radiating member 161 (161d) and the second heat radiating member 162 (162d) are formed at different heights, so that heat dissipation can be improved.

  In the fourth and fifth embodiments, the first heat radiating member 161 and the second heat radiating member 162 are made of the same material as the first source field plate electrode 151 and the second source field plate electrode 152. Thus, heat conducted from the vicinity of the first gate electrode 121 and the vicinity of the second gate electrode 122 can be radiated more easily than the first source field plate electrode 151 and the second source field plate electrode 152 alone. . Further, the first heat radiating member 161 and the second heat radiating member 162 are made of a metal having a higher thermal conductivity than the first source field plate electrode 151 and the second source field plate electrode 152, thereby improving heat dissipation. May be.

  The material of the first source field plate electrode 151 and the second source field plate electrode 152 is, for example, an alloy of titanium (Ti) and aluminum (Al). Therefore, heat dissipation can be improved by forming the first heat radiating member 161 and the second heat radiating member 162 from gold (Au), copper (Cu), or an alloy thereof having a higher thermal conductivity than the alloy. .

  In the embodiment, the semiconductor substrate 10 has a structure in which aluminum gallium nitride (AlGaN) is stacked on gallium nitride (GaN) or gallium nitride. In addition, the semiconductor substrate 10 may have a structure in which aluminum gallium arsenide (AlGaAs) is stacked on gallium arsenide (GaAs) or gallium arsenide.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

10 ... Semiconductor substrate,
11, 111, 112... Source electrode,
12, 121, 122... Gate electrode,
13 ... drain electrode,
14. Insulator layer,
15, 151, 152... Source field plate electrode,
16, 161, 162 ... Radiating fins (heat radiating members),
17, 171, 172... Connection portion.

Claims (13)

A semiconductor substrate;
A gate electrode formed on the semiconductor substrate;
A source electrode and a drain electrode formed on the semiconductor substrate, spaced apart from the gate electrode and sandwiching the gate electrode;
An insulator layer covering the semiconductor substrate and the gate electrode between the gate electrode, the source electrode and the drain electrode;
A source field plate electrode formed on at least the insulator layer closer to the drain electrode than the gate electrode and electrically connected to the source electrode;
A heat dissipating member formed on the source field plate electrode and dissipating heat generated near the gate electrode to the outside of the semiconductor;
A semiconductor device comprising:   2. The semiconductor device according to claim 1, wherein the source field plate electrode is further formed to extend on the insulator layer formed on the gate electrode.   The semiconductor device according to claim 1, wherein at least a part of the heat dissipating member is exposed to the air.   4. The semiconductor device according to claim 1, wherein the heat dissipation member extends in a direction orthogonal to the semiconductor substrate and has a substantially uniform width along the extending direction.   4. The semiconductor device according to claim 1, wherein the heat radiating member extends in a direction orthogonal to the semiconductor substrate, and the width decreases or increases along the extending direction. The semiconductor device according to claim 1, wherein the heat radiating member is formed along a longitudinal direction of the source field plate electrode and formed at different heights along the longitudinal direction.   The semiconductor device according to claim 1, wherein the heat radiating member is made of the same material as the source field plate electrode or a metal having higher thermal conductivity than the source field plate electrode. .   The semiconductor device according to claim 1, wherein the heat radiating member is made of gold, copper, or an alloy thereof. A semiconductor substrate;
A first gate electrode formed on the semiconductor substrate;
A first source electrode and a drain electrode formed on the semiconductor substrate and spaced apart from the first gate electrode and sandwiching the first gate electrode;
A second gate electrode provided apart from the drain electrode;
A second source electrode provided apart from the second gate electrode;
On the semiconductor substrate between the first gate electrode, the first source electrode and the drain electrode, and on the semiconductor substrate between the second gate electrode, the second source electrode and the drain electrode; An insulator layer covering the first gate electrode and the second gate electrode;
A first source field plate electrode formed on at least the insulator layer closer to the drain electrode than the first gate electrode and electrically connected to the first source electrode;
A second source field plate electrode formed on at least the insulator layer closer to the drain electrode than the second gate electrode and electrically connected to the second source electrode;
A first heat dissipating member formed on the first source field plate electrode and dissipating heat generated in the vicinity of the first gate electrode to the outside of the semiconductor;
A second heat dissipating member formed on the second source field plate electrode and dissipating heat generated in the vicinity of the second gate electrode to the outside of the semiconductor;
Have
The semiconductor device in which the first heat radiating member and the second heat radiating member are provided to face each other.   The first source field plate electrode is further formed to extend on the insulator layer formed on the first gate electrode, and the second source field plate electrode is further formed from the second source field plate electrode. The semiconductor device according to claim 9, wherein the semiconductor device extends on the insulator layer formed on the gate electrode.   11. The semiconductor device according to claim 9, wherein at least a part of the first heat radiating member and the second heat radiating member is exposed to the air.   10. The first heat radiation member and the second heat radiation member are formed at different heights along a longitudinal direction of the first source field plate electrode and the second source field plate electrode. The semiconductor device according to claim 11.   13. The semiconductor device according to claim 12, wherein the first heat radiating member and the second heat radiating member are formed at different heights at portions facing each other along the longitudinal direction.

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