JP2009038307A - Semiconductor device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device such as a high electron mobility transistor and a magnetic sensor, etc., acting as an amplifying element for transmission and reception for satellite broadcast or as a high-speed data transfer element, and a method for manufacturing it. <P>SOLUTION: This device includes a substrate 1, a first Al<SB>y</SB>Ga<SB>1-y</SB>As<SB>z</SB>Sb<SB>1-z</SB>layer (0≤y≤1, 0≤z<1) 2 provided on the substrate 1, an In<SB>x</SB>Ga<SB>1-x</SB>As layer (0≤x≤1) 3 acting as an electron transit layer provided on the first Al<SB>y</SB>Ga<SB>1-y</SB>As<SB>z</SB>Sb<SB>1-z</SB>layer 2, and a second Al<SB>y</SB>Ga<SB>1-y</SB>As<SB>z</SB>Sb<SB>1-z</SB>layer (0≤y≤1, 0≤z<1) 4 provided on the In<SB>x</SB>Ga<SB>1-x</SB>As layer 3. One or both of the first Al<SB>y</SB>Ga<SB>1-y</SB>As<SB>z</SB>Sb<SB>1-z</SB>layer 2 and the second Al<SB>y</SB>Ga<SB>1-y</SB>As<SB>z</SB>Sb<SB>1-z</SB>layer 4 are doped with Sn, and act as an electron supplying layer to the In<SB>x</SB>Ga<SB>1-x</SB>As electron transit layer 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor device and a manufacturing method thereof, and more specifically, a high electron mobility transistor (hereinafter abbreviated as HEMT) suitable as a transmission / reception amplifying element for satellite broadcasting or a high-speed data transfer element. And a manufacturing method thereof.

A HEMT is known as a high-frequency element in the GHz band typified by a transmission / reception amplifying element for satellite broadcasting. Typical examples include those in which a GaAs layer on a GaAs substrate or an In _0.53 Ga _0.47 As layer on an InP substrate is used as an electron transit layer, all of which are heterogeneous of GaAs and AlGaAs, InGaAs and InAlAs. It utilizes a two-dimensional electron gas layer that accumulates at the structure interface.

  However, a HEMT having an extremely short gate length of 0.2 μm or less is required to obtain an element capable of transmitting and receiving radio waves in the tens of GHz band by these elements. In order to form a gate electrode having such a length, optical lithography may be used. However, advanced technology is required, and stable production is not easy. In addition, if the gate length is shortened, there is a problem in transistor characteristics such as an increase in noise due to an increase in gate resistance and a decrease in gain.

  Therefore, there is a demand for a high-frequency device having a new structure that can be easily miniaturized, is mass-productive, and can handle a higher frequency band than before. That is, a high-frequency element that has a high electron traveling speed in the electron traveling layer and can cope with a high frequency band even with a relatively long gate length is preferable. Furthermore, in such a high-frequency device, if the gate length is further reduced to 0.2 μm or less, or 0.1 μm or less, application to the millimeter wave band, which is a high-frequency band, can be expected. Application to the field becomes possible.

In order to meet these demands, high _- quality thin films of InAs and high In concentration In _x Ga _1-x As, which have an overwhelmingly high electron mobility and saturation speed, are used for GaAs and In _0.53 Ga _0.47 As. Research for use in the electronic travel layer is being conducted. The feature of high electron mobility is an important characteristic for realizing a highly sensitive sensor in a magnetic sensor such as a Hall element and a magnetoresistive element, and the same applies to the application to a magnetic sensor. The high electron mobility and saturation speed of InAs and In _x Ga _1-x As with a high In concentration are sufficient even in a HEMT having a longer gate length than a HEMT using GaAs or In _0.53 Ga _0.47 As as an electron transit layer. There is a possibility of realizing a high-frequency device corresponding to several GHz band or higher frequency band.

However, in realizing In _x Ga _1-x As based HEMT of InAs and high In concentration are either electron supply layer is any material is an important issue. That is, the discontinuous value between the conduction band of the electron supply layer and the conduction band of the channel is large enough to confine electrons in the electron transit layer, the electron concentration value is appropriate, and the electron transit layer. It is necessary to be a material that can be well matched with InAs or high In concentration In _x Ga _1-x As.

  For example, according to Patent Document 1, on a general-purpose GaAs substrate having a lattice constant different from InAs, an AlGaAsSb layer substantially lattice-matched with InAs, an InAs layer as an electron transit layer, and further lattice-matched substantially with InAs A field effect transistor (hereinafter abbreviated as FET) having excellent high-frequency characteristics is realized by adopting a structure in which AlGaAsSb layers to be stacked are sequentially laminated.

  Here, an InAs layer using only electrons generated in the layer as carriers is used as the electron transit layer, and no electron supply by intentional doping is performed. These carriers are supplied from an unintentionally doped donor impurity in AlGaAsSb or from the interface between AlGaAsSb and InAs. In order to obtain a HEMT having a lower on-resistance (large transconductance), the sheet resistance of the InAs layer must be lowered, and the electron concentration must be further increased. That is, a technique for increasing the electron concentration without reducing the electron mobility of the InAs electron transit layer is essential. Establishing such a technology is an extremely important issue in creating a magnetic sensor with high sensitivity and good temperature characteristics.

First, as a method for increasing the electron concentration of the In _x Ga _1-x As electron transit layer of InAs or high In concentration and In _x Ga _1-x As doped directly donor impurities in the electron transit layer of InAs or high In concentration There is a way. Any donor impurity may be used as long as it acts as a donor atom, and examples thereof include Te, Se, S, Si, and Sn. However, in this case, the donor impurity becomes an impurity scattering source in the InAs or high In concentration In _x Ga _1-x As layer, and the electron mobility is lowered.

As another method for increasing the electron concentration of the InAs or high In concentration In _x Ga _1-x As electron transit layer, there is a method using modulation doping. In this structure, the InAs or high In concentration In _x Ga _1-x As electron transit layer is not doped with donor impurities, and only the AlGaAsSb layer is doped with donor impurities. At this time, due to the discontinuity of the conduction band of InAs or high In concentration In _x Ga _1-x As and AlGaAsSb, electrons accumulate on the side of InAs at the heterointerface or high In concentration In _x Ga _1-x As. Occur.

That is, since the electron affinity of InAs or high In concentration In _x Ga _1-x As is large, electrons supplied by donor impurities in the AlGaAsSb layer are attracted to the InAs or high In concentration In _x Ga _1-x As side. To form a two-dimensional electron gas layer. Since InAs and high In concentration In _x Ga _1-x As layers are not doped with donor impurities, high electron mobility can be obtained without the influence of impurity scattering. Here, the position where the donor impurity is doped may be uniform or distributed in the thickness direction of the AlGaAsSb layer. For example, the AlGaAsSb layer may be delta-doped with donor impurities.

  Te, Se, S, Sn, Si, etc. are generally known as n-type dopants for III-V compound semiconductors. Among them, the IV group element Si is most widely used. This is because Si has a low vapor pressure and can be easily controlled in the temperature range of a flux source used in a standard molecular beam epitaxy (hereinafter abbreviated as MBE) process.

However, in antimony compounds such as AlSb and GaSb, it has become clear that Si acts as an acceptor impurity (see, for example, Non-Patent Document 1). Furthermore, even in AlGaSb, which is a mixed crystal of AlSb and GaSb, and in AlGaAsSb, which has a lattice constant close to that of InAs or high In concentration In _x Ga _1-x As, Si is an acceptor impurity and forms an electron supply layer of AlGaAsSb. Can not do it.

  Therefore, as a donor impurity to the AlGaAsSb layer, Te, which is a VI group element that works sufficiently as a donor impurity even in an antimony compound such as AlSb or GaSb, is used (for example, see Non-Patent Document 1). However, since Te has a very high vapor pressure, the temperature range of the flux source used in the standard MBE process is very low, it is difficult to change the doping amount rapidly, and its control is not easy. Furthermore, since Te has a very high vapor pressure, it is very likely to remain in the MBE apparatus. This residue contaminates the MBE apparatus and hinders the p-type process of the subsequent process using the apparatus, which is not industrially preferable.

Therefore, it is preferable to use a group IV element that is easy to handle as a donor impurity for the AlGaAsSb layer. Sn, which is an IV group element like Si, is a dopant material that has a relatively low vapor pressure and is easy to handle. Non-Patent Document 1 describes that Sn also acts as an acceptor impurity in antimony compounds such as AlSb and GaSb. However, when Sn is actually doped into the AlGaAsSb layer, it is not clear whether it functions as an electron supply layer to the InAs electron transit layer. For this reason, a HEMT or magnetic sensor using an AlGaAsSb layer functioning as an electron supply layer cannot be realized for an InAs or high In concentration In _x Ga _1-x As electron transit layer.

Japanese Patent Laid-Open No. 5-90301 (Japanese Patent No. 3200142) Physica E20 (2004) 196-203, Herbert Kroemer, UCSB

As described above, by using a group IV element having a low vapor pressure as a donor impurity, the electron concentration of the InAs or high In concentration In _x Ga _1-x As electron transit layer can be accurately adjusted without contaminating the MBE device. A technique for easily increasing the electron concentration without reducing the electron mobility of the InAs or high In concentration In _x Ga _1-x As electron transit layer has not been established.

The present invention has been made in view of such a situation, and an object of the present invention is to use InAs or high In concentration In _x Ga ₁₋ as a donor impurity by using a group IV element Sn having a low vapor pressure as a donor impurity. The electron concentration of the _x As channel layer can be easily and accurately controlled without contaminating the MBE device, and without reducing the electron mobility of the In As or high In concentration In _x Ga _1-x As electron transit layer. By establishing a technique for increasing the electron concentration, an object is to provide a semiconductor device such as a HEMT or a high-sensitivity magnetic sensor having excellent high-frequency characteristics, and a manufacturing method thereof.

In order to achieve such an object, the present invention provides an In _x Ga _1-x As layer (0 ≦ x ≦ 1) and an Al _y Ga _1-y As _z Sb _1- A semiconductor device having at least one heterojunction with a _z layer (0 ≦ y ≦ 1, 0 ≦ z <1), wherein at least one of the Al _y Ga _1-y As _z Sb _1-z layers Is doped with Sn and serves as an electron supply layer to the In _x Ga _1-x As layer, which is an electron transit layer.

The invention according to claim 2 is the invention according to claim 1, wherein the Al _y Ga _1-y As _z Sb _1-z layer is doped with Sn doped Al _y Ga _1-y As. _{A z} Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1) is provided.

The invention according to claim 3 is the invention according to claim 1, wherein a Sn delta-doped layer is provided in the Al _y Ga _1-y As _z Sb _1-z layer. And

The invention described in claim 4 is directed to an In _x Ga _1-x As layer (0 ≦ x ≦ 1) and an Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z). <1) A semiconductor device having at least one heterojunction with a substrate and a first Al _y Ga _{1 -y} As _z Sb _{1 -z} layer (0 ≦ y ≦ 1) provided on the substrate , 0 ≦ z <1) and an In _x Ga _1-x As layer (0 ≦ x ≦) as an electron transit layer provided on the _first Al _y Ga _1-y As _z Sb _1-z layer. 1) and a second Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1) provided on the In _x Ga _1-x As layer comprising, one of the first or second _{Al y Ga 1-y As z} Sb 1-z layer, and at least one of _{Al y Ga 1-y As z} Sb 1-z in layer Sn is doped, it has become a donor layer to said in _x Ga _1-x as layer And features.

The invention according to claim 5 is the invention according to claim 4, wherein the Al _y Ga _1-y As _z Sb _1-z layer is doped with Sn-doped Al _y Ga _1-y As. _{A z} Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1) is provided.

The invention according to claim 6 is the invention according to claim 4, wherein a Sn delta-doped layer is provided in the Al _y Ga _1-y As _z Sb _1-z layer. And

The invention according to claim 7 is the invention according to claim 2 or 5, wherein the In _x Ga _1-x As and the Sn doped Al _y Ga _1-y As _z Sb _1-z layer. The thickness of the Al _y Ga _{1 -y} As _z Sb _{1 -z} layer that is not doped with Sn is between 2.5 nm and 20 nm.

The invention according to claim 8 is the invention according to claim 3 or 6, wherein the Al _y Ga not doped with Sn, which is between the In _x Ga _1-x As and the delta doped layer. _{The 1-y} As _z Sb _1-z layer has a thickness of 2.5 nm to 20 nm.

The invention described in claim 9 is directed to an In _x Ga _1-x As layer (0 ≦ x ≦ 1) and an Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z). <1) A method of manufacturing a semiconductor device having at least one heterojunction with an undoped first Al _y Ga _1-y As _z Sb _1-z (0 ≦ y ≦ 1, 0 ≦ z <1) forming a layer, and an In _x Ga _1-x As layer (0 ≦ x) as an electron transit layer on the _first Al _y Ga _1-y As _z Sb _1-z layer ≦ 1) and an undoped second Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z) on the In _x Ga _1-x As layer. <1), forming a Sn delta-doped layer on the Al _y Ga _1-y As _z Sb ₁ -z layer, and undoped third Al on the Sn delta-doped layer _y Ga _1-y As _z Sb Forming a _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1).

  Further, in the invention described in claim 10, in the invention described in claim 9, the step of forming the delta doped layer comprises simultaneously using Sn and Sb or simultaneously using Sn, As and Sb by molecular beam epitaxy. Irradiating.

  According to an eleventh aspect of the present invention, there is provided the semiconductor device according to any one of the first to eighth aspects, a source electrode and a drain electrode that are in ohmic contact with the semiconductor device, and the semiconductor device. A high electron mobility transistor including a gate electrode.

  According to a twelfth aspect of the present invention, there is provided a magnetic sensor comprising the semiconductor device according to any one of the first to eighth aspects and an ohmic electrode formed on the semiconductor device.

According to the present invention, by using the IV group element Sn, which has a low vapor pressure and is easy to handle, as the donor impurity of the AlGaAsSb electron supply layer, the In _x Ga _1-x As can be easily obtained without contaminating the MBE apparatus. The electron concentration of the channel layer can be controlled. Therefore, since an In _x Ga _1-x As channel layer having a high electron concentration and a high electron mobility can be manufactured industrially stably, as an amplifying element for transmitting and receiving satellite broadcasts and an element for high-speed data transfer, It is possible to provide a semiconductor device such as a HEMT or a high-sensitivity magnetic sensor having excellent high-frequency characteristics, and a manufacturing method thereof.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view for explaining an embodiment of a high electron mobility transistor (HEMT) according to the present invention, in which reference numeral 1 denotes a substrate, and 2 denotes a first Al _y Ga _1-y As _z Sb _1-z. Reference numeral 3 denotes an In _x Ga _1-x As electron transit layer, and 4 denotes a second Al _y Ga _1-y As _z Sb _1-z layer. 5 and 7 are a pair of ohmic electrodes, 5 is a source electrode, and 7 is a drain electrode. Reference numeral 6 denotes a gate electrode provided between the source electrode 5 and the drain electrode 7.

The high electron mobility transistor (HEMT) of the present invention includes an In _x Ga _1-x As layer (0 ≦ x ≦ 1) and an Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0). It is a semiconductor device having at least one heterojunction with ≦ z <1). Specifically, the substrate 1, the first Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1) 2 provided on the substrate 1, An In _x Ga _1-x As layer (0 ≦ x ≦ 1) 3 as an electron transit layer provided on the first Al _y Ga _1-y As _z Sb _1-z layer 2, and this In _x Ga _A second Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1) 4 provided on the _1-x As layer 3.

Here, Sn is doped in one or both of the first Al _y Ga _{1 -y} As _z Sb _{1 -z} layer 2 and the second Al _y Ga _{1 -y} As _z Sb _{1 -z} layer 4. Thus, it is an electron supply layer to the In _x Ga _1-x As electron transit layer 3. Further, either one of the first Al _y Ga _{1 -y} As _z Sb _{1 -z} layer 2 and the second Al _y Ga _{1 -y} As _z Sb _{1 -z} layer 4 is not present, or another semiconductor Even when it is a material, it has at least one heterojunction between the Sn-doped Al _y Ga _1-y As _z Sb _1-z layer and the In _x Ga _1-x As electron transit layer 3. Any thin film structure is within the technical scope of the present invention. Hereinafter, each component will be described.

The substrate 1 used in the present invention may be anything as long as it is a substrate, but a GaAs substrate, a GaP substrate, a Si substrate with a single crystal GaAs grown on the surface, a sapphire substrate, or the like is preferable. Among these, a GaAs substrate that can provide a semi-insulating and high-quality single crystal substrate is particularly preferable. Here, the semi-insulating property means that the resistivity is 10 ⁷ Ω · cm or more. When a single crystal substrate is used, the surface orientation of the substrate is preferably (100), (111), (110), or the like. A plane orientation shifted from 1 ° to 5 ° from these plane orientations may be used. Among these, (100) is optimal for growing a high-quality thin film. As usual, for the purpose of flattening and cleaning the surface of the substrate, a semiconductor grown of the same material as the substrate may be used as the substrate of the present invention. The most typical example is the growth of GaAs on a GaAs substrate.

The first Al _y Ga _1-y As _z Sb _1-z layer 2 used in the present invention has a lattice constant close to that of the (a) In _x Ga _1-x As electron transit layer 3, and (b) In _x Even when the resistivity is sufficiently higher than that of the Ga _1-x As electron transit layer 3 and (c) directly laminated on a substrate of GaAs or the like having a lattice constant greatly different from that of the In _x Ga _1-x As electron transit layer 3, It is preferable to have a flat surface with few defects. The lattice constants of the first Al _y Ga _1-y As _z Sb _1-z layer 2 and the In _x Ga _1-x As electron transit layer 3 are such that the film thickness of the In _x Ga _1-x As electron transit layer 3 is critical. It suffices if it is close to the thickness not exceeding the film thickness. For example, when the thickness of the In _x Ga _1-x As electron transit layer 3 is 15 nm, the first Al _y Ga _1-y As _z Sb _1-z layer 2 and the In _x Ga _1-x As electron transit layer 3 It is preferable that the lattice constants coincide with each other within 1.3%.

In _x Ga _1-x As (0 ≦ x ≦ 1) When the In composition x of the electron transit layer 3 is 0.53 or more and 1 or less, the first Al _y Ga _1-y As _z Sb _1-z (0 ≦ y ≦ 1, 0 ≦ z <1) The As composition z of the layer 2 is preferably 0 or more and 0.7 or less. While the resistivity of the first Al _y Ga _1-y As _z Sb _1-z layer 2 increases as the Al composition y increases, there is a concern that it is likely to be oxidized during the device fabrication process. It is preferably in the range of 0.5 to 0.8.

Flatness of the first _{Al y Ga 1-y As z} Sb 1-z layer 2 of the surface, but film thickness is thicker the better industrially is possible it is desirable to thin. That is, the film thickness is preferably in the range of 5 nm to 3000 nm, more preferably 10 nm to 1000 nm. When the first Al _y Ga _{1 -y} As _z Sb _{1 -z} layer 2 is used as an electron supply layer to the In _x Ga _{1 -x} As electron transit layer 3, Sn is uniformly doped in the thickness direction. May be distributed or delta-doped. In particular, the first Al _y Ga _{1 -y} As _z Sb _{1 -z} layer 2 in the vicinity of the interface with the In _x Ga _{1 -x} As electron transit layer 3 has a structure in which Sn is not doped, thereby affecting the influence of impurity scattering. Can be reduced, and high electron mobility can be obtained.

  Here, delta doping is a doping technique performed by simultaneously irradiating a dopant and a group V element in the thin film growth of a group III-V compound semiconductor using a molecular beam epitaxy method. Since the group III element is not irradiated, the thin film growth is performed in a state where the growth does not proceed. As a result, the film thickness of the delta doped layer is as close to zero as possible, strictly speaking, it is about several atomic layers. Delta doping is preferred because it allows a desired amount of doping at a desired location.

The In _x Ga _1-x As (0 ≦ x ≦ 1) electron transit layer 3 used in the present invention preferably has a film thickness of 2000 nm or less for the purpose of controlling electrical conduction by the voltage applied to the control electrode. More preferably, it is 5 nm or more and 100 nm or less. Further, when the electron concentration of the In _x Ga _1-x As electron transit layer 3 is 3 × 10 ¹⁷ cm ⁻³ or more and 2 × 10 ¹⁸ cm ⁻³ or less, high electron mobility is preferable. The In _x Ga _{1 -x} As (0 ≦ x ≦ 1) electron transit layer 3 is preferable because the higher the In composition x, the higher the electron mobility is obtained. In particular, the In composition x is 0.53 or more and 1 or less. Is preferred.

The second Al _y Ga _1-y As _z Sb _1-z layer 4 used in the present invention has a lattice constant close to that of (a) In _x Ga _1-x As electron transit layer 3, and (b) In _x It is preferable that the resistivity is sufficiently higher than that of the Ga _1-x As electron transit layer 3. The lattice constants of the second Al _y Ga _1-y As _z Sb _1-z layer 4 and the In _x Ga _1-x As electron transit layer 3 are such that the film thickness of the In _x Ga _1-x As electron transit layer 3 is critical. It suffices if it is close to the thickness not exceeding the film thickness. For example, when the thickness of the In _x Ga _1-x As electron transit layer 3 is 15 nm, the second Al _y Ga _1-y As _z Sb _1-z layer 4 and the In _x Ga _1-x As electron transit layer 3 It is preferable that the lattice constants coincide with each other within 1.3%. In _x Ga _1-x As (0 ≦ x ≦ 1) When the In composition x of the electron transit layer 3 is 0.53 or more and 1 or less, the second Al _y Ga _1-y As _z Sb _1-z (0 ≦ y ≦ 1, 0 ≦ z <1) The As composition z of the layer 4 is preferably 0 or more and 0.7 or less.

The resistivity of the second Al _y Ga _1-y As _z Sb _1-z layer 4 increases as the Al composition y increases, while there is a concern that it is likely to be oxidized during the device fabrication process, and the Al composition y is 0. It is preferably in the range of 0.5 to 0.8. The film thickness of the second Al _y Ga _1-y As _z Sb _1-z layer 4 is preferably in the range of 5 nm to 100 nm. When the second Al _y Ga _{1 -y} As _z Sb _{1 -z} layer 4 is used as an electron supply layer to the In _x Ga _{1 -x} As channel layer 3, Sn may be uniformly doped in the thickness direction. , May be distributed or may be delta doped. In particular, a structure in which Sn is not doped only in the vicinity of the interface on the side where the gate electrode 6 is formed is favorable because the gate breakdown voltage does not decrease.

Further, the second Al _y Ga _{1 -y} As _z Sb _{1 -z} layer 4 in the vicinity of the interface with the In _x Ga _{1 -x} As electron transit layer 3 has a structure in which Sn is not doped, whereby impurity scattering is achieved. This is preferable because the influence of the above can be reduced and high electron mobility can be obtained. Since the first Al _y Ga _{1 -y} As _z Sb _{1 -z} layer 2 and the second Al _y Ga _{1 -y} As _z Sb _{1 -z} layer 4 have the same composition, the manufacturing process can be simplified. Although it is preferable, it may have a different composition and is appropriately carried out as necessary.

The source electrode 5 and the drain electrode 7 used in the present invention are required to form an ohmic contact with the underlying In _x Ga _1-x As electron transit layer 3. The ohmic junction has various structures. In FIG. 1, the ohmic junction is directly joined to the In _x Ga _1-x As electron transit layer 3. The In _x Ga _1-x As electron transit layer 3 has a narrow band gap, and an ohmic junction with a low contact resistance can be obtained simply by contacting the electrodes. For this reason, the second Al _y Ga _{1 -y} As _z Sb _{1 -z} layer 4 is etched only at the lower part of the ohmic electrodes 5 and 7, and an electrode is formed directly on the In _x Ga _{1 -x} As channel layer 3. Can do. In this case, in order to reduce the contact resistance between the electrodes 5 and 7 and the In _x Ga _1-x As channel layer 3, an alloying process may be performed, but a good ohmic junction can be obtained only by vapor deposition. . For this reason, the electrode metal may be a well-known laminated electrode structure including a three-layer structure of AuGe / Ni / Au, but may be a single-layer metal such as Al, Ti, Au, W, and so many combinations are possible. It is.

Gate electrodes 6 used in the present invention, as long as it can form a depletion layer thereunder, in addition to the method of using a Schottky junction, between the gate electrode and the In _x Ga _1-x As electron transit layer 3 In addition, a MIS (METAL-INSULATOR-SEMICONDUCTOR) structure with an insulator interposed therebetween or a PN junction can be used. In particular, as a material for forming the Schottky junction with the second Al _y Ga _1-y As _z Sb _1-z layer 4, Al, Ti, W, Pt, WSi, Au, and the like are preferable. What you did is also good.

FIG. 10 is a flowchart illustrating a method for manufacturing a high electron mobility transistor according to the present invention.
The high electron mobility transistor of the present invention includes an In _x Ga _1-x As layer (0 ≦ x ≦ 1) and an Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <). This is a method for manufacturing a semiconductor device having at least one heterojunction with 1).

First, in step 1 (S1), an undoped first Al _y Ga _1-y As _z Sb _1-z (0 ≦ y ≦ 1, 0 ≦ z <1) layer is formed on the substrate. Next, in Step 2 (S2), an In _x Ga _1-x As layer (0 ≦ x ≦ 1) as an electron _transit layer is formed on the first Al _y Ga _1-y As _z Sb _1-z layer. Form. Next, in step 3 (S3), an undoped second Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z) is formed on the In _x Ga _1-x As layer. <1) is formed. Next, in step 4 (S4), a Sn delta-doped layer is formed on the Al _y Ga _{1 -y} As _z Sb ₁ -z layer. Finally, in step 5 (S5), an undoped third Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1) is formed on the Sn delta doped layer. To do. Further, in step 4 for providing a delta doped layer, Sn and Sb are simultaneously irradiated or Sn, As and Sb are simultaneously irradiated by a molecular beam epitaxy method.

Specific examples of the present invention will be described below, but the present invention is not limited to these examples.
[Example 1]
As an example of the thin film forming method, a case where a molecular beam epitaxy method (MBE method) is used will be described below. First, surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, an undoped Al _0.53 Ga _0.47 Sb layer having a film thickness of 600 nm is grown while lowering the substrate temperature to 460 ° C., and then an InAs layer having a film thickness of 15 nm is grown while maintaining the substrate temperature at 460 ° C. An undoped Al _0.53 Ga _0.47 Sb layer of Sn was heated on the Sn cell temperature to 950 ° C., and Sn and Sb were simultaneously irradiated for 56 seconds to form a Sn delta doped layer thereon. An undoped Al _0.53 Ga _0.47 Sb layer having a thickness of 30 nm was grown. Further, in this embodiment, in order to prevent oxidation of the outermost surface of the Al _0.53 Ga _0.47 Sb layer, a GaAs cap layer grown on the undoped Al _0.53 Ga _0.47 Sb layer as a semiconductor protective layer.

As a result of evaluating the electrical characteristics of this thin film laminate by van der Pauw method and hole measurement, the electron mobility was 30300 cm ² / Vs, and the sheet electron concentration was 1.60 × 10 ¹² cm ⁻² . Here, the electron mobility is the speed of movement of electrons per unit electric field, and the sheet electron concentration is the number of electrons per cm ² . In the thin film stack without the Sn delta-doped layer, the electron mobility is 25300 cm ² / Vs and the sheet electron concentration is 5.9 × 10 ¹¹ cm ^−2. It has a high value, and the effect of the Sn delta doped layer is found to be very large. From this result, it was clarified that the group IV element Sn, which has been said to work as an acceptor, works as a donor. Compared with a group VI element such as Te, it is extremely preferable in the industry that the electron concentration of the electron transit layer can be controlled with a group IV element Sn having a low vapor pressure, easy handling, and no fear of contamination of the chamber.

  In these thin film stacks, after passing through the mesa etching process, the portions where the source and drain electrodes are formed are etched to expose the InAs surface, and the source and drain electrodes are formed directly on the InAs, and the GaAs cap layer A high electron mobility transistor HEMT was manufactured by forming a gate electrode thereon.

In this example, the Sn delta doped layer is formed by irradiating at a site 5 nm away from the interface between InAs and Al _0.53 Ga _0.47 Sb layer with the Sn cell temperature heated to 950 ° C. for 56 seconds. .

Here, the value of the sheet electron concentration of the thin film stack when the position of the Sn delta doped layer (distance from the interface between InAs and Al _0.53 Ga _0.47 Sb layer) and the time of irradiation with Sn are changed are shown in FIG. And shown in FIG.

FIG. 2 is a graph showing the relationship between the position of the Sn delta doped layer (distance from the interface between InAs and Al _0.53 Ga _0.47 Sb layer) and the sheet electron concentration of the thin film stack, and FIG. It is the figure which showed the relationship between the processing time and the sheet | seat electron density | concentration of a thin film laminated body on the graph.

The Sn cell temperature at this time is 950 ° C. FIG. 2 shows that the sheet electron concentration is high when the dope position is close, and the sheet electron concentration is low when the dope position is far. This is probably because the probability that electrons in the AlGaAsSb electron supply layer fall into the InAs electron transit layer decreases as the doping position increases. From FIG. 3, it was found that the sheet electron concentration monotonously increased as the Sn irradiation time was increased. From these results, the sheet electron concentration of the thin film stack can be easily controlled only by controlling the position of the Sn delta doped layer (distance from the interface between InAs and Al _0.53 Ga _0.47 Sb layer) and the time of irradiation with Sn. I found that I can do it.

FIG. 4 is a graph showing the relationship between the sheet electron concentration and the electron mobility of the thin film laminate. Here, all data in which the Sn doping position is changed from 2.5 nm to 20 nm, the Sn cell temperature is changed from 930 ° C. to 970 ° C., and the Sn irradiation time is changed from 0 second to 94 seconds are plotted. FIG. 4 shows that the electron mobility is high when the sheet electron concentration is 5 × 10 ¹¹ cm ⁻² or more and 3 × 10 ¹² cm ⁻³ or less, that is, the electron concentration is 3 × 10 ¹⁷ cm ⁻³ or more and 2 × 10 ¹⁸ cm ⁻³ or less. It can be seen that In particular, the electron mobility is 30000 cm at 1.2 × 10 ¹² cm ⁻² or more and 1.6 × 10 ¹² cm ⁻² or less, that is, at an electron concentration of 8 × 10 ¹⁷ cm ⁻³ or more and 1.1 × 10 ¹⁸ cm ⁻³ or less. ² / Vs or more, which is preferable.

FIG. 5 is a graph showing the relationship between the position of the Sn delta doped layer (distance from the interface between InAs and Al _0.53 Ga _0.47 Sb layer) and the electron mobility of the thin film stack. The Sn cell temperature at this time is 950 ° C., and the Sn irradiation time is 56 seconds. If the doping position is too close, InAs will be affected by Sn impurity scattering, and the electron mobility will be reduced. On the contrary, if the doping position is far, the sheet electron concentration is lowered, so that the electron mobility is lowered. The electron mobility is preferably 27000 (cm ² / Vs) or more. From the results of FIG. 5, the position of the Sn delta doped layer (distance from the interface between InAs and Al _0.53 Ga _0.47 Sb layer) is 2.5 nm. It is preferable that it is 20 nm or less.

[Example 2]
After forming the above-described thin film laminate into a cross shape by a mesa etch process, the InAs surface is exposed by etching only the portions where the electrodes are to be formed, and the electrodes are formed on the InAs, so that the Hall element that is a magnetic sensor is formed. Produced.

  6 is a cross-sectional view showing the structure of the fabricated Hall element, and FIG. 7 is a top view showing the structure of the fabricated Hall element. Reference numeral 9 denotes an ohmic electrode.

The electrical characteristics of the thin film stack used at this time are an electron mobility of 30300 cm ² / Vs, a sheet resistance of 158Ω, and a sheet electron concentration of 1.30 × 10 ¹² cm ⁻² . The characteristics obtained with the Hall element of this example were that the Hall voltage was 75 mV when a magnetic flux density of 50 mT was applied when the input resistance value was 300 Ω and the constant voltage was 1 V. That is, the sensitivity in the magnetic field was as high as 75 mV / V · 50 mT.

[Example 3]
A magnetoresistive element, which is a magnetic sensor, was produced using the thin film laminate of Example 1 described above. The electrical characteristics of the thin film stack used at this time are an electron mobility of 30700 cm ² / Vs, a sheet resistance of 144Ω, and a sheet electron concentration of 1.42 × 10 ¹² cm ⁻² .

FIG. 8 is a cross-sectional view showing the structure of the produced magnetoresistive element, and FIG. 9 is a top view showing the structure of the produced magnetoresistive element.
After forming into a strip shape by the mesa etching process, only the portion where the electrode is formed is etched to expose the InAs surface, and the ohmic electrode 9 and the short-circuit electrode 10 are formed on the InAs to produce a magnetoresistive element. The length of the magnetoresistive element portion made of an InAs thin film excluding the terminal electrode portion is 1450 μm, the width of the InAs thin film is 120 μm, and the Cu / Ni / Au / Ni layer formed across the InAs magnetoresistive element portion having a width of 120 μm. The four-layered short-circuit electrode has a length of 120 μm and a width of 9 μm, and was formed in direct contact with the InAs thin film at regular intervals. The resistance value between the electrodes was 1200Ω when no magnetic field was applied.

  In order to detect a weak magnetic field change with high sensitivity, which is also a magnetic flux density region applied when the magnetoresistive element is used as a magnetic sensor, that is, a magnetic flux density region in which the magnetoresistive change linearly changes to the magnetic flux density. The absolute resistance change rate at a magnetic flux density of 0.45 T, which is also the region of the bias magnetic flux density, was 160%, indicating a very large magnetoresistance change.

[Example 4]
As an example of the thin film forming method, a case where a molecular beam epitaxy method (MBE method) is used will be described below. First, surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, an undoped Al _0.53 Ga _0.47 Sb layer having a film thickness of 600 nm is grown while lowering the substrate temperature to 460 ° C., and then an InAs layer having a film thickness of 15 nm is grown while maintaining the substrate temperature at 460 ° C. An undoped Al _0.53 Ga _0.47 Sb layer of Sn was heated on the Sn cell temperature to 950 ° C., and Sn and Sb were simultaneously irradiated for 75 seconds to form a Sn delta doped layer thereon. An undoped Al _0.53 Ga _0.47 Sb layer having a thickness of 30 nm was grown. Further, the purpose in this embodiment for preventing the oxidation of the outermost surface of the Al _0.53 Ga _0.47 Sb layer, a GaAs cap layer grown on the undoped Al _0.53 Ga _0.47 Sb layer as a semiconductor protective layer.

The thin film laminate had an electron mobility of 28000 cm ² / Vs and a sheet electron concentration of 2.16 × 10 ¹² cm ⁻² . In the thin film stack without the Sn delta-doped layer, the electron mobility is 25300 cm ² / Vs and the sheet electron concentration is 5.9 × 10 ¹¹ cm ^−2. It has a high value, and the effect of the Sn delta doped layer is found to be very large. Although the electron mobility is slightly reduced as compared with Example 1, it is possible to obtain higher sheet electron density characteristics by increasing the Sn irradiation time.

[Example 5]
As an example of the thin film forming method, a case where a molecular beam epitaxy method (MBE method) is used will be described below. First, surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, an undoped Al _0.53 Ga _0.47 Sb layer having a thickness of 600 nm is grown while lowering the substrate temperature to 460 ° C., and then an InAs layer having a thickness of 15 nm is grown while maintaining the substrate temperature at 460 ° C. An Al _0.53 Ga _0.47 Sb layer doped with Sn was grown. Further, in this embodiment in order to prevent oxidation of the outermost surface of the Al _0.53 Ga _0.47 Sb layer, a GaAs cap layer grown on Sn doped Al _0.53 Ga _0.47 Sb layer as a semiconductor protective layer.

The thin film laminate had an electron mobility of 24300 cm ² / Vs and a sheet electron concentration of 2.11 × 10 ¹² cm ⁻² . In the thin film stack without the Sn doped layer, the electron mobility is 25300 cm ² / Vs and the sheet electron concentration is 5.9 × 10 ¹¹ cm ^−2. It has a high value, and the effect of the Sn doped layer was found to be very large.

[Example 6]
As an example of the thin film forming method, a case where a molecular beam epitaxy method (MBE method) is used will be described below. First, surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, an undoped Al _0.53 Ga _0.47 Sb layer having a thickness of 600 nm is grown while lowering the substrate temperature to 460 ° C., and then an InAs layer having a thickness of 15 nm is grown while maintaining the substrate temperature at 460 ° C. after growing the Al _0.53 Ga _0.47 Sb layer doped with Sn of, and an undoped Al _0.53 Ga _0.47 Sb layer of a thickness of 15 nm. Further, in this embodiment in order to prevent oxidation of the outermost surface of the Al _0.53 Ga _0.47 Sb layer, a GaAs cap layer grown on Sn doped Al _0.53 Ga _0.47 Sb layer as a semiconductor protective layer.

The thin film laminate had an electron mobility of 25100 cm ² / Vs and a sheet electron concentration of 1.88 × 10 ¹² cm ⁻² . In the thin film stack without the Sn doped layer, the electron mobility is 25300 cm ² / Vs and the sheet electron concentration is 5.9 × 10 ¹¹ cm ^−2. It has a high value, and the effect of the Sn doped layer was found to be very large.

[Example 7]
As an example of the thin film forming method, a case where a molecular beam epitaxy method (MBE method) is used will be described below. First, surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, an undoped Al _0.53 Ga _0.47 Sb layer having a film thickness of 600 nm is grown while lowering the substrate temperature to 460 ° C., and then an InAs layer having a film thickness of 15 nm is grown while maintaining the substrate temperature at 460 ° C. After growing the undoped Al _0.53 Ga _0.47 Sb layer, an Al _0.53 Ga _0.47 Sb layer doped with 30 nm thick Sn was grown. Further, in this embodiment in order to prevent oxidation of the outermost surface of the Al _0.53 Ga _0.47 Sb layer, a GaAs cap layer grown on Sn doped Al _0.53 Ga _0.47 Sb layer as a semiconductor protective layer.

The thin film laminate had an electron mobility of 29500 cm ² / Vs and a sheet electron concentration of 1.36 × 10 ¹² cm ⁻² . In the thin film stack without the Sn doped layer, the electron mobility is 25300 cm ² / Vs and the sheet electron concentration is 5.9 × 10 ¹¹ cm ^−2. It has a high value, and the effect of the Sn doped layer was found to be very large.

[Example 8]
As an example of the thin film forming method, a case where a molecular beam epitaxy method (MBE method) is used will be described below. First, surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, an undoped Al _0.53 Ga _0.47 Sb layer having a thickness of 600 nm was grown while lowering the substrate temperature to 460 ° C., and then an InAs layer having a thickness of 15 nm was grown while maintaining the substrate temperature at 460 ° C. undoped Al _0.53 Ga _0.47 Sb layer having a thickness of 5nm, Al _0.53 Ga _0.47 Sb layer doped with Sn with a thickness of 15 nm, were sequentially grown an undoped Al _0.53 Ga _0.47 Sb layer of a thickness of 15 nm. Further, in this embodiment in order to prevent oxidation of the outermost surface of the Al _0.53 Ga _0.47 Sb layer, a GaAs cap layer grown on Sn doped Al _0.53 Ga _0.47 Sb layer as a semiconductor protective layer.

The thin film laminate had an electron mobility of 30100 cm ² / Vs and a sheet electron concentration of 1.31 × 10 ¹² cm ⁻² . In the thin film stack without the Sn doped layer, the electron mobility is 25300 cm ² / Vs and the sheet electron concentration is 5.9 × 10 ¹¹ cm ^−2. It has a high value, and the effect of the Sn doped layer was found to be very large.

[Example 9]
As an example of the thin film forming method, a case where a molecular beam epitaxy method (MBE method) is used will be described below. First, surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, after growing an undoped Al _0.53 Ga _0.47 Sb layer with a film thickness of 595 nm while lowering the substrate temperature to 460 ° C., Sn and Sb are simultaneously irradiated for 56 seconds with the Sn cell temperature heated to 950 ° C. Then, a delta-doped layer of Sn was formed, and an undoped Al _0.53 Ga _0.47 Sb layer having a thickness of 5 nm was grown thereon. Further, an InAs layer having a thickness of 15 nm was grown while maintaining the substrate temperature at 460 ° C., and then an undoped Al _0.53 Ga _0.47 Sb layer having a thickness of 35 nm was grown. Further, in order to prevent oxidation of the outermost surface of the Al _0.53 Ga _0.47 Sb layer in this embodiment, the GaAs cap layer grown on the undoped Al _0.53 Ga _0.47 Sb layer as a semiconductor protective layer.

The thin film laminate had an electron mobility of 30500 cm ² / Vs and a sheet electron concentration of 1.49 × 10 ¹² cm ^-2 . In the thin film stack without the Sn delta-doped layer, the electron mobility is 25300 cm ² / Vs and the sheet electron concentration is 5.9 × 10 ¹¹ cm ^−2. It has a high value, and the effect of the Sn delta doped layer is found to be very large. Further, even when compared with Example 1, the same characteristics were obtained, and it became clear that the AlGaAsSb layer under the InAs electron transit layer also functions as an electron supply layer by doping Sn.

[Example 10]
A case where a molecular beam epitaxy method (MBE method) is used as an example of the thin film forming method will be described in detail. First, the surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, an undoped Al _0.53 Ga _0.47 Sb layer having a film thickness of 600 nm is grown while lowering the substrate temperature to 460 ° C., and then an InAs layer having a film thickness of 15 nm is grown while maintaining the substrate temperature at 460 ° C. An undoped Al _0.53 Ga _0.47 Sb layer of Sn was heated on the Sn cell temperature to 950 ° C., and Sn and Sb were simultaneously irradiated for 56 seconds to form a Sn delta doped layer thereon. An undoped Al _0.53 Ga _0.47 Sb layer having a thickness of 30 nm was grown. For the purpose in the present embodiment to prevent the oxidation of the outermost surface of the Al _0.53 Ga _0.47 Sb layer, an InAs cap layer grown on the undoped Al _0.53 Ga _0.47 Sb layer as a semiconductor protective layer.

The thin film laminate had an electron mobility of 29500 cm ² / Vs and a sheet electron concentration of 1.26 × 10 ¹² cm ⁻² . In the thin film stack without the Sn delta-doped layer, the electron mobility is 23300 cm ² / Vs and the sheet electron concentration is 5.4 × 10 ¹¹ cm ⁻² . Therefore, in this embodiment, both the electron mobility and the electron concentration are used. It has a high value, and the effect of the Sn delta doped layer is found to be very large. In addition, the same characteristics as in Example 1 are obtained, and even when the cap layer is made of InAs, the effect of the Sn delta doped layer is very large.

[Example 11]
As an example of the thin film forming method, a case where a molecular beam epitaxy method (MBE method) is used will be described below. First, surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, an undoped Al _0.65 Ga _0.35 Sb layer having a thickness of 600 nm is grown while lowering the substrate temperature to 460 ° C., and then an InAs layer having a thickness of 15 nm is grown while maintaining the substrate temperature at 460 ° C. An undoped Al _0.65 Ga _0.35 Sb layer of Sn is heated on the Sn cell temperature to 950 ° C., and Sn and Sb are simultaneously irradiated for 56 seconds to form a Sn delta-doped layer. An undoped Al _0.65 Ga _0.35 Sb layer having a thickness of 30 nm was grown. Further, in order to prevent oxidation of the outermost surface of the Al _0.65 Ga _0.35 Sb layer in this embodiment, the GaAs cap layer grown on the undoped Al _0.65 Ga _0.35 Sb layer as a semiconductor protective layer.

The thin film laminate had an electron mobility of 28700 cm ² / Vs and a sheet electron concentration of 1.39 × 10 ¹² cm ⁻² . In the thin film stack without the Sn delta doped layer, the electron mobility is 21500 cm ² / Vs and the sheet electron concentration is 5.1 × 10 ¹¹ cm ^−2. It has a high value, and the effect of the Sn delta doped layer is found to be very large. In addition, although the electron mobility is slightly lowered as compared with Example 1, the effect of the Sn delta doped layer is very large.

[Example 12]
As an example of the thin film forming method, a case where a molecular beam epitaxy method (MBE method) is used will be described below. First, surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, an undoped Al _0.8 Ga _0.2 Sb layer having a thickness of 600 nm is grown while lowering the substrate temperature to 460 ° C., and then an InAs layer having a thickness of 15 nm is grown while maintaining the substrate temperature at 460 ° C. An undoped Al _0.8 Ga _0.2 Sb layer of Sn was heated on the Sn cell temperature to 950 ° C., and Sn and Sb were irradiated at the same time for 56 seconds to form a Sn delta doped layer thereon. A 30 nm thick undoped Al _0.8 Ga _0.2 Sb layer was grown. Further, in order to prevent oxidation of the outermost surface of the Al _0.8 Ga _0.2 Sb layer in this embodiment, the GaAs cap layer grown on the undoped Al _0.8 Ga _0.2 Sb layer as a semiconductor protective layer.

The thin film laminate had an electron mobility of 25700 cm ² / Vs and a sheet electron concentration of 1.41 × 10 ¹² cm ⁻² . In the thin film stack without the Sn delta-doped layer, the electron mobility is 17100 cm ² / Vs and the sheet electron concentration is 4.1 × 10 ¹¹ cm ⁻² . Therefore, in this example, both the electron mobility and the electron concentration are used. It has a high value, and the effect of the Sn delta doped layer is found to be very large. In addition, although the electron mobility is slightly lowered as compared with Example 1, the effect of the Sn delta doped layer is very large.

[Example 13]
As an example of the thin film forming method, a case where a molecular beam epitaxy method (MBE method) is used will be described below. First, surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, an undoped Al _0.53 Ga _0.47 As _0.13 Sb _0.87 layer having a thickness of 600 nm is grown while the substrate temperature is lowered to 460 ° C., and then an InAs layer having a thickness of 15 nm is grown while the substrate temperature is maintained at 460 ° C. An undoped Al _0.53 Ga _0.47 As _0.13 Sb _0.87 layer with a thickness of 5 nm is formed, and a Sn delta doped layer is formed by simultaneously irradiating Sn and Sb for 56 seconds with the Sn cell temperature heated to 950 ° C. An undoped Al _0.53 Ga _0.47 As _0.13 Sb _0.87 layer having a thickness of 30 nm was grown thereon. For the purpose in the present embodiment to prevent the oxidation of the outermost surface of the Al _0.53 Ga _0.47 As _0.13 Sb _0.87 layer, the GaAs cap layer grown on the undoped Al _0.53 Ga _0.47 As _0.13 Sb _0.87 layer on the semiconductor protective layer.

The thin film laminate had an electron mobility of 23000 cm ² / Vs and a sheet electron concentration of 1.67 × 10 ¹² cm ⁻² . In the thin film stack without the Sn delta-doped layer, the electron mobility is 15800 cm ² / Vs and the sheet electron concentration is 3.2 × 10 ¹¹ cm ⁻² . Therefore, in this example, both the electron mobility and the electron concentration are used. It has a high value, and the effect of the Sn delta doped layer is found to be very large. In addition, although the electron mobility is slightly lowered as compared with Example 1, the effect of the Sn delta doped layer is very large.

[Example 14]
As an example of the thin film forming method, a case where a molecular beam epitaxy method (MBE method) is used will be described below. First, surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, an undoped Al _0.53 Ga _0.47 As _0.13 Sb _0.87 layer having a thickness of 600 nm was grown while the substrate temperature was lowered to 460 ° C., and then an InAs layer having a thickness of 30 nm was grown while the substrate temperature was maintained at 460 ° C. An undoped Al _0.53 Ga _0.47 As _0.13 Sb _0.87 layer with a thickness of 5 nm is formed, and a Sn delta doped layer is formed by simultaneously irradiating Sn and Sb for 56 seconds with the Sn cell temperature heated to 950 ° C. An undoped Al _0.53 Ga _0.47 As _0.13 Sb _0.87 layer having a thickness of 30 nm was grown thereon. For the purpose in the present embodiment to prevent the oxidation of the outermost surface of the Al _0.53 Ga _0.47 As _0.13 Sb _0.87 layer, the GaAs cap layer grown on the undoped Al _0.53 Ga _0.47 As _0.13 Sb _0.87 layer on the semiconductor protective layer.

The thin film laminate had an electron mobility of 24700 cm ² / Vs and a sheet electron concentration of 1.86 × 10 ¹² cm ^-2 . In the thin film stack without the Sn delta-doped layer, the electron mobility is 21300 cm ² / Vs and the sheet electron concentration is 5.6 × 10 ¹¹ cm ⁻² . Therefore, in this embodiment, both the electron mobility and the electron concentration are used. It has a high value, and the effect of the Sn delta doped layer is found to be very large. Compared to Example 13, higher electron mobility and sheet electron concentration can be obtained.

[Example 15]
As an example of the thin film forming method, a case where a molecular beam epitaxy method (MBE method) is used will be described below. First, surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, an undoped Al _0.53 Ga _0.47 As _0.3 Sb _0.7 layer having a thickness of 600 nm was grown while lowering the substrate temperature to 460 ° C., and then an In _0.8 Ga _0.2 As layer having a thickness of 15 nm was maintained while maintaining the substrate temperature at 460 ° C. Then, an undoped Al _0.53 Ga _0.47 As _0.3 Sb _0.7 layer having a thickness of 5 nm is further grown, and Sn and Sb are simultaneously irradiated for 56 seconds with the Sn cell temperature heated to 950 ° C. A delta-doped layer was formed, and an undoped Al _0.53 Ga _0.47 As _0.3 Sb _0.7 layer having a thickness of 30 nm was grown thereon. For the purpose in the present embodiment to prevent the oxidation of the outermost surface of the Al _0.53 Ga _0.47 As _0.3 Sb _0.7 layer, the GaAs cap layer grown on the undoped Al _0.53 Ga _0.47 As _0.3 Sb _0.7 layer on the semiconductor protective layer.

The thin film laminate had an electron mobility of 11300 cm ² / Vs and a sheet electron concentration of 1.42 × 10 ¹² cm ⁻² . In the thin film stack without the Sn delta-doped layer, the electron mobility is 5600 cm ² / Vs and the sheet electron concentration is 5 × 10 ¹⁰ cm ⁻² . In this example, both the electron mobility and the electron concentration are high. The effect of the Sn delta doped layer was found to be very large. In addition, although the electron mobility is reduced as compared with Example 1, the effect of the Sn delta doped layer is very large.

[Example 16]
As an example of the thin film forming method, a case where a molecular beam epitaxy method (MBE method) is used will be described below. First, surface oxygen is desorbed by heating at 630 ° C. while irradiating a semi-insulating GaAs (100) substrate with As. After the substrate temperature is lowered to 580 ° C. as it is, a GaAs buffer layer having a thickness of 70 nm is grown, and further, a GaAs buffer layer having a thickness of 35 nm is grown while the substrate temperature is lowered to 530 ° C. Next, an undoped Al _0.53 Ga _0.47 As _0.2 Sb _0.8 layer having a thickness of 600 nm was grown while the substrate temperature was lowered to 460 ° C., and then an In _0.8 Ga _0.2 As layer having a thickness of 15 nm was maintained while maintaining the substrate temperature at 460 ° C. Then, an undoped Al _0.53 Ga _0.47 As _0.2 Sb _0.8 layer having a thickness of 5 nm is further grown, and Sn and Sb are simultaneously irradiated for 56 seconds with the Sn cell temperature heated to 950 ° C. A delta-doped layer was formed, and an undoped Al _0.53 Ga _0.47 As _0.2 Sb _0.8 layer having a thickness of 30 nm was grown thereon. For the purpose in the present embodiment to prevent the oxidation of the outermost surface of the Al _0.53 Ga _0.47 As _0.2 Sb _0.8 layer, the GaAs cap layer grown on the undoped Al _0.53 Ga _0.47 As _0.2 Sb _0.8 layer on the semiconductor protective layer.

The thin film laminate had an electron mobility of 11700 cm ² / Vs and a sheet electron concentration of 1.29 × 10 ¹² cm ⁻² . In the thin film stack without the Sn delta-doped layer, the electron mobility is 8100 cm ² / Vs and the sheet electron concentration is 2.4 × 10 ¹¹ cm ⁻² . Therefore, in this embodiment, both the electron mobility and the electron concentration are used. It has a high value, and the effect of the Sn delta doped layer is found to be very large. In addition, although the electron mobility is slightly lowered as compared with Example 1, the effect of the Sn delta doped layer is very large.

It is sectional drawing for demonstrating one Embodiment of the high electron mobility transistor (HEMT) by this invention. Position of the Sn delta doped layer is a diagram showing a graph and a sheet electron concentration of the relationship of the thin film stack (distance from the interface between the InAs and Al _0.53 Ga _0.47 Sb layer). It is the figure which showed the relationship between the time which irradiated Sn, and the sheet electron density | concentration of a thin film laminated body in the graph. It is the figure which showed the relationship between the sheet electron density | concentration and electron mobility of a thin film laminated body on the graph. It illustrates in a graph and the electron mobility of the relationship (the distance from the interface between InAs and Al _0.53 Ga _0.47 Sb layer) position of the Sn delta doped layer of the thin film stack. It is sectional drawing which shows the structure of the produced Hall element. It is a top view which shows the structure of the produced Hall element. It is sectional drawing which shows the structure of the produced magnetoresistive element. It is a top view which shows the structure of the produced magnetoresistive element. It is a figure which shows the flowchart for demonstrating the manufacturing method of the high electron mobility transistor (HEMT) by this invention.

Explanation of symbols

1 substrate 2 first _{Al y Ga 1-y As z} Sb 1-z layer 3 In _x Ga _1-x As electron transit layer 4 second _{Al y Ga 1-y As z} Sb 1-z layer 5 source electrode ,
6 Gate electrode 7 provided between source electrode 5 and drain electrode 7 Drain electrode 8 Thin film laminate 9 Ohmic electrode 10 Short-circuit electrode

Claims (12)

At least one heterojunction between the In _x Ga _1-x As layer (0 ≦ x ≦ 1) and the Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1). A semiconductor device comprising:
At least one of the Al _y Ga _1-y As _z Sb _1-z layers is doped with Sn, and serves as an electron supply layer to the In _x Ga _1-x As layer, which is an electron transit layer. A semiconductor device characterized by comprising: In the Al _y Ga _1-y As _z Sb _1-z layer, there is an Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1) doped with Sn. The semiconductor device according to claim 1, wherein the semiconductor device is provided. The semiconductor device according to claim 1, wherein a delta-doped layer of Sn is provided in the Al _y Ga _1-y As _z Sb _1-z layer. At least one heterojunction between the In _x Ga _1-x As layer (0 ≦ x ≦ 1) and the Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1). A semiconductor device comprising:
A substrate, a first Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1) provided on the substrate, and the first Al _y Ga ₁₋ in _x Ga _1-x as layer as an electron transit layer formed on the _y as _z Sb _1-z layer (0 ≦ x ≦ 1), provided on said in _x Ga _1-x as layer A second Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1),
Of the first or second Al _y Ga _{1 -y} As _z Sb _{1 -z} layer, at least one Al _y Ga _{1 -y} As _z Sb _{1 -z} layer is doped with Sn, and the In A semiconductor device which is an electron supply layer to the _x Ga _1-x As layer. In the Al _y Ga _1-y As _z Sb _1-z layer, there is an Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1) doped with Sn. The semiconductor device according to claim 4, wherein the semiconductor device is provided. The semiconductor device according to claim 4, wherein a Sn delta-doped layer is provided in the Al _y Ga _1-y As _z Sb ₁ -z layer. Between the In _x Ga _1-x As and the Sn-doped Al _y Ga _1-y As _z Sb _1-z layer, the Al _y Ga _1-y As _z Sb undoped with Sn 6. The semiconductor device according to claim 2, wherein the thickness of the _1-z layer is 2.5 nm or more and 20 nm or less. The film thickness of the Al _y Ga _{1 -y} As _z Sb ₁ -z layer, which is not doped with Sn, between the In _x Ga _{1 -x} As and the delta doped layer is 2.5 nm or more and 20 nm or less. The semiconductor device according to claim 3, wherein the semiconductor device is provided. At least one heterojunction between the In _x Ga _1-x As layer (0 ≦ x ≦ 1) and the Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1). A method for manufacturing a semiconductor device comprising:
Forming an undoped first Al _y Ga _1-y As _z Sb _1-z (0 ≦ y ≦ 1, 0 ≦ z <1) layer on the substrate; and the first Al _y Ga ₁₋ on the _y as _z Sb _1-z layer to form in _x Ga _1-x as layer as an electron transit layer (0 ≦ x ≦ 1), on top of the in _x Ga _1-x as layer Forming an undoped second Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ z <1), and the Al _y Ga _1-y As _z Sb _1- forming a Sn delta-doped layer on the _z- layer, and an undoped third Al _y Ga _1-y As _z Sb _1-z layer (0 ≦ y ≦ 1, 0 ≦ on the Sn delta-doped layer) and a step of forming z <1).   10. The method of manufacturing a semiconductor device according to claim 9, wherein the step of forming the delta doped layer irradiates Sn and Sb simultaneously or Sn, As and Sb simultaneously by a molecular beam epitaxy method.   A semiconductor device according to any one of claims 1 to 8, a source electrode and a drain electrode that are ohmic-bonded on the semiconductor device, and a gate electrode provided on the semiconductor device. Electron mobility transistor.   A magnetic sensor comprising: the semiconductor device according to claim 1; and an ohmic electrode formed on the semiconductor device.

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