This application claims priority from Japanese Patent Application No. 2023-143876 filed on Sep. 5, 2023. The content of this application is incorporated herein by reference in its entirety.
The present disclosure relates to a semiconductor device and a power amplification module.
As a technology for increasing the efficiency of a power amplification circuit mounted on a radio communication terminal, there is known a semiconductor device in which a power amplifier is configured by electrically connecting a plurality of transistors in parallel on one single chip (see, for example, Japanese Patent No. 2580966). Also, there is known a multi-finger type heterojunction bipolar transistor in which high output and miniaturization are both achieved by connecting a plurality of heterojunction bipolar transistors (HBTs), which can perform high efficiency operation, in parallel in a row in the short side direction of the emitter fingers (see, for example, Japanese Unexamined Patent Application Publication No. 2007-027269). Japanese Unexamined Patent Application Publication No. 2007-027269 discloses a structure in which non-uniformity of heat generated in the HBT cells is taken into account. Specifically, since the emitter fingers in the central portion are affected by the heat from the emitter fingers in the peripheral portions, the temperature of the emitter fingers in the central portion become higher.
In recent years, there has been a desire for a power amplification device that can be used even in extremely cold regions, such as those below-30 degrees Centigrade. A bipolar transistor such as an HBT generally has a lower breakdown voltage under a low temperature environment. Thus, there is a possibility that, under a cryogenic environment below-30 degrees Centigrade, for example, overvoltage may occur at junctions located in the end portions of the device.
The present disclosure provides a semiconductor device and a power amplification module capable of expanding the lower limit of an operating temperature range.
A semiconductor device according to an aspect of the present disclosure includes: a first semiconductor element in which a plurality of transistors arranged in one direction are electrically connected in parallel; and a second semiconductor element provided in both end portions in the arrangement direction of the transistors, wherein the lower an ambient temperature is, the greater a current flowing through the second semiconductor element relatively increases.
In such a configuration, the lower the ambient temperature is, the more the heating value of the second semiconductor element increases, and therefore the more the junction temperature at the position corresponding to the junction of the second semiconductor element rises. Accordingly, the closer to the junction of the second semiconductor element, the more the junction temperature rises at the position corresponding to each junction of the first semiconductor element.
A power amplification module according to an aspect of the present disclosure includes: the semiconductor device described above; a substrate on which the semiconductor device is flip-chip mounted; and a bump provided between the semiconductor device and the substrate, wherein, in plan view, the bump is provided in a region overlapping the first semiconductor element and is not provided in a region overlapping the second semiconductor element.
In such a configuration, the heat dissipation from the position corresponding to the junction of the second semiconductor element is suppressed. As a result, the junction temperature at the position corresponding to the junction of the second semiconductor element can be increased.
A power amplification module according to an aspect of the present disclosure includes: the semiconductor device described above; and a substrate on which the semiconductor device is wire-bonded, wherein, in plan view, the semiconductor device is provided with a heat dissipating via in a region overlapping the first semiconductor element and is not provided with the heat dissipating via in a region overlapping the second semiconductor element.
In such a configuration, the heat dissipation from the position corresponding to the junction of the second semiconductor element is suppressed. As a result, the junction temperature at the position corresponding to the junction of the second semiconductor element can be increased.
According to the present disclosure, it is possible to realize a semiconductor device and a power amplification module capable of expanding the lower limit of the operating temperature range.
A semiconductor device and a power amplification module according to each embodiment will be described in detail below with reference to the drawings. The present disclosure is not limited by the embodiment. Each embodiment is an example; and it is needless to say that partial replacement or combination of the configurations shown in the different embodiments is possible. In Embodiment 2 and subsequent embodiments, the description of matters common to Embodiment 1 will be omitted, and only different points will be described. In particular, similar effects by similar configurations will not be referred to one by one in each embodiment.
In the present disclosure, the power amplification module 100 is not limited to a PA having a configuration of two stages, as shown in
In the present disclosure, the power amplification module 100 is an ultra-compact integrated module in which a plurality of integrated circuits and various functional components are mounted on a substrate 2 formed of, for example, a ceramic laminated substrate, such as a low-temperature co-fired ceramic (LTCC) substrate, a resin multilayer substrate, a film substrate, or the like.
As the semiconductor device 200, an HBT device (integrated circuit) composed of, for example, GaAs (gallium arsenide) based heterojunction bipolar transistors (HBTs) is exemplified.
In the present disclosure, the semiconductor device 200 includes a semiconductor element 1 having N junctions 1_n (n is an integer from 2 to N) arranged in the X direction. Specifically, the semiconductor element 1 is a bipolar transistor having a so-called multi-finger structure in which N transistors Tr1_n are electrically connected in parallel. Here, the term “junction” refers to a junction in which a p-type semiconductor and an n-type semiconductor are pn-junctioned; and as an example, the junction between the base layer and the collector layer of the bipolar transistor is shown. Each junction 1_n shown in
The emitter of each transistor Tr1_n is electrically connected to a reference potential. The reference potential is exemplified by a ground potential GND; however, in the present disclosure, the reference potential is not limited the ground potential GND.
A high-frequency input signal RFin is inputted to the base of each transistor Tr1_n via a capacitor C. A current supplied from a bias circuit 30 via a resistor RB1 flows through the base of each transistor Tr1_n. The sum of the currents flowing through the base of each transistor Tr1_n is equal to a bias current Ib1 supplied from the bias circuit 30.
A power supply potential VCC is applied to the collector of each transistor Tr1_n. The high-frequency signal power-amplified by the semiconductor element 1 is outputted as a high-frequency output signal RFout.
In the configuration shown in
The bias circuit 30, to which a bias power supply potential Vbat is applied, supplies the bias current Ib1, which corresponds to a bias control current Ib1ctrl, to the semiconductor element 1. The bias control current Ib1ctrl is supplied from, for example, a control circuit (not shown) provided inside or outside the power amplification module 100.
The bipolar transistors constituting the semiconductor device 200 generally have lower breakdown voltages under a low temperature environment.
As shown in
Due to non-uniformity of the heat dissipation of the semiconductor device 200, there is a possibility that overvoltage may occur at the junctions located in the end portions of the device under a low temperature environment, so that the required specification of the operating temperature range may be unmet. Hereinafter, a configuration of a semiconductor device and a power amplification device capable of expanding the lower limit of the operating temperature range will be described.
In the semiconductor device 20 according to Embodiment 1, the configuration of a first semiconductor element 1 is substantially the same as that of the semiconductor element 1 described with reference to
The semiconductor device 20 according to Embodiment 1 includes, in addition to the first semiconductor element 1, a second semiconductor element provided with junctions 2_1 and 2_2 at both end portions in the arrangement direction of the junction 1_n (X direction). In Embodiment 1, the second semiconductor element is transistors Tr2_1 and Tr2_2. The junctions 2_1 and 2_2 shown in
The emitters of the transistors Tr2_1 and Tr2_2 are electrically connected to the reference potential. Bias currents Ib2_1 and Ib2_2 supplied from a bias circuit 40 via a resistor RB2 flow through the base of each of the transistors Tr2_1 and Tr2_2. A power supply potential VCC is supplied to the collectors of the transistors Tr2_1 and Tr2_2 via resistors RC. That is, the resistors RC are provided between the collector of each transistor Tr1_n, which is the power feeding point of the power supply potential VCC to the first semiconductor element 1, and the collectors of the transistors Tr2_1 and Tr2_2, which are the power feeding points of the power supply potential VCC to the second semiconductor element.
In the configuration shown in
In the configuration shown in
In
In
In
As shown in
In contrast, as shown in
In the configuration shown in
Embodiment 2 describes a configuration that includes: a temperature sensor (thermistor) 50 that detects an ambient temperature; an AD conversion circuit 61 that converts the value detected by the temperature sensor 50 to digital; a control current generation circuit 62 that generates a bias control current Ib2ctrl supplied to a bias circuit 40a; and a storage circuit 63 that stores, as a current control table, the relationship between the temperature detected by the temperature sensor 50 and the bias control current Ib2ctrl.
The control current generation circuit 62 refers to the current control table stored in the storage circuit 63 to generate the bias control current Ib2ctrl, which corresponds to the value detected by the temperature sensor 50. The bias circuit 40a supplies a bias current Ib2, which corresponds to the bias control current Ib2ctrl, to the second semiconductor element (transistors Tr2_1 and Tr2_2). Thus, it is easy to change the temperature setting.
In Embodiment 3, a second semiconductor element is diodes D2_1 and D2_2. The junctions of the diodes D2_1 and D2_2 correspond to the junctions 2_1 and 2_2 shown in
In each configuration of Embodiment 3 shown in
Alternatively, in each configuration of Embodiment 3 shown in
The substrate 2 is provided with a plurality of reference potential surfaces 22 (GND layers) with a plurality of dielectric layers 21 interposed therebetween, and the reference potential surfaces 22 are connected to each other by through-vias 23 to form a heat dissipation structure. In the power amplification module 10a according to Embodiment 4 shown in
As shown in
The configuration of the substrate 2 is the same as that of Embodiment 4. As shown in
In the embodiments described above, the transistor constituting the semiconductor device 200 is exemplified by a bipolar transistor; however, the transistor constituting the semiconductor device 200 is not limited to being a bipolar transistor, but may be, for example, a MOSFET. In such a case as well, due to non-uniformity of heat dissipation of the semiconductor device, there is a possibility that, under a low temperature environment, overvoltage may occur in the channel portions of the MOSFET located in the end portions of the device, so that the required specification of the operating temperature range may be unmet.
The embodiments described above are intended to facilitate understanding of the present disclosure, and are not intended to limit the interpretation thereof. The present disclosure may be changed/modified without necessarily departing from its scope, and the present disclosure also includes equivalents thereof.
The present disclosure may have the following configurations as described above or in lieu of the above.
(1) A semiconductor device according to an aspect of the present disclosure includes: a first semiconductor element in which a plurality of transistors arranged in one direction are electrically connected in parallel; and a second semiconductor element provided in both end portions in the arrangement direction of the transistors, wherein the lower an ambient temperature is, the greater a current flowing through the second semiconductor element relatively increases.
In such a configuration, the lower the ambient temperature is, the more the heating value of the second semiconductor element increases, and therefore the more the junction temperature at the position corresponding to the junction of the second semiconductor element rises. Accordingly, the closer to the junction of the second semiconductor element, the more the junction temperature rises at the position corresponding to each junction of the first semiconductor element.
(2) In the semiconductor device according to (1), the second semiconductor element is a transistor.
In such a configuration, the lower the ambient temperature is, the more the heating value of the transistor increases, and therefore the more the junction temperature at the position corresponding to the junction of second semiconductor element rises. Accordingly, the closer to the junction of the transistor, the more the junction temperature rises at the position corresponding to each junction of the first semiconductor element.
(3) In the semiconductor device according to (2), a resistor is provided between a power feeding point to the first semiconductor element and a power feeding point to the second semiconductor element.
In such a configuration, isolation between the first semiconductor element and the second semiconductor element is ensured.
(4) In the semiconductor device according to (1), the second semiconductor element is a diode.
In such a configuration, the lower the ambient temperature is, the more the heating value of the diode increases, and therefore the more the junction temperature at the position corresponding to the junction of the diode rises. Accordingly, the closer to the junction of the diode, the more the junction temperature rises at the position corresponding to each junction of the first semiconductor element.
(5) A power amplification module according to an aspect of the present disclosure includes: the semiconductor device described above; a substrate on which the semiconductor device is flip-chip mounted; and a bump provided between the semiconductor device and the substrate, wherein, in plan view, the bump is provided in a region overlapping the first semiconductor element and is not provided in a region overlapping the second semiconductor element.
In such a configuration, the heat dissipation from the position corresponding to the junction of the second semiconductor element is suppressed. As a result, the junction temperature at the position corresponding to the junction of the second semiconductor element can be increased.
(6) A power amplification module according to an aspect of the present disclosure includes: the semiconductor device described above; and a substrate on which the semiconductor device is wire-bonded, wherein, in plan view, the semiconductor device is provided with a heat dissipating via in a region overlapping the first semiconductor element and is not provided with the heat dissipating via in a region overlapping the second semiconductor element.
In such a configuration, the heat dissipation from the position corresponding to the junction of the second semiconductor element is suppressed. As a result, the junction temperature at the position corresponding to the junction of the second semiconductor element can be increased.
According to the present disclosure, it is possible to realize a semiconductor device and a power amplification module capable of expanding the lower limit of the operating temperature range.
Number | Date | Country | Kind |
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2023-143876 | Sep 2023 | JP | national |