JPH07506461A - Integrated circuit with quantum well p-channel field effect transistor and complementary transistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] A collection with quantum well n-channel field effect transistors and complementary transistors. product circuit The present invention can be applied to n-channel electric fields alone or in integrated circuits of complementary transistors. Quantum well n-channel field effect transistor used in combination with effect transistor This relates to resistor-type parts.

In this respect, CMOS silicon has a memory capacity of 0.1 bit per month. Low value of 3μW and thus enable large-scale integration of complex digital circuits. Its low power consumption makes it a very promising technology.

However, with this technology, due to the long propagation time of CMOS silicon, ultra-high speed The circuit cannot be obtained: therefore, when memory access obtained with this technique The distance is about Ions.

If you want higher speed, for example, silicon that enables access times on the order of Ins. Implementing the circuit with another technology, such as based on ECL bipolar transistors on There is a need to.

But this circuit requires much more power, on the order of a few hundred microwatts per bit. Consume.

Another possibility is to use III-V alloys instead of silicon. In particular, Ga M E S F E Ts manufactured on As (MEtal-3emicon ductor Field-Effect Transistors: Electric field effect (metal-semiconductor transistors). But this middle This technology has no industrial importance, as the target value is only a compromise between speed and power consumption. No suitable field of use has been found.

The fastest circuits realized to date include AlGaAs/GaAs heterojunctions. HEMTs (High Electron Mobility Tran It was realized based on high electron mobility transistors (sisters: high electron mobility transistors), but this part The product is TEGFETs (TEGFETs) with a propagation time of about 25 to 30 ps per logic gate. to-DiII lenional Electron Gas Field- Effect Transistors: Two-dimensional electron gas field effect transistors It is also known by the abbreviation ``ta''. However, the power consumption is 4mW per logic gate. Due to its large size, large-scale integration is very difficult.

More recently, AlGaAs/Ga1nAs heterojunction integrated circuits have been fabricated. proposed, but similar to the case of CMO3, n- and p-channel complementary transistors This is a particularly interesting technique because it uses data. For example, D, E, Grider DeveloppH1ent of 5tatic Random Acce ss Memories Using Complemen 狽≠Nitrogen■ Heterostructure In5ulated Gate Field Effect Transistor Technolo A GaAs Ic 5ynposiu+++ Digest 1990. See p. 143. can be seen. With this technology, the propagation time is relatively short, about 200 ps, and the It is possible to realize integrated circuits with extremely low power consumption of approximately 64 μW per chip. Ru. In this way, access time is 3.51s, which is extremely high performance, and power consumption is reduced. A 4-bit static memory SRAM with a very low 183 mW was realized (see, Delta-Doped Complellenta of D., E. Grider et al. ry Heterostructure FET5 with High Y- Value　Pseudomo Nittar ■奄■ In+Ga+-rAs Channels for tlltra Low I 'ower Digital ICA Application Katana AIED) I Digest 1991. (See p. 235).

The present invention is based on the well-known parts of AlGaAs/Ga1nAs heterojunctions proposed so far. The aim is to overcome some of the imperfections and limitations of the product (to be discussed in more detail later). target

More precisely, one of the objects of the invention is to The transconductance value is about the same as that of an n-channel transistor. A complementary circuit that has the same performance as a +1 channel transistor. n-channel transistor with very high transconductance that can be realized The aim is to suggest the appropriate thickness and epitaxial layer selection to realize the star. .

This has not been possible until now because n-channel transistors However, its 141 mutual conductance is less than a quarter of that of an n-channel transistor. This is because it was. The physical phenomena that cause these differences will be discussed later. I will explain in detail.

According to a first feature of the invention, a component adopting the conventional structure of a heterojunction is proposed. It will be done.

More precisely, this well-known structure is based on wide forbidden III-V semiconductor materials (G AlxGa+-xAs on aAs substrate or AIr In+- on InP substrate rAs) and a narrow bandgap III-V semiconductor material (preferably rAs). A heterogeneous layer formed between layers containing (preferably Ga, In+-yAs) The heterojunction consists of a heterojunction at the level of the layer containing the narrow forbidden material. A quantum well is formed to form an HH type side band in the valence band structure of the B structure.

The first feature of the present invention described in 0;I is that when a negative voltage is applied to the gate, the amount of In the child well there are side bands HH1 and HH2, and in some cases higher order side bands HHs... , are essentially selected such that these various side bands have the highest effective mass m ``The side band corresponding to h// has a much lower density than the density of holes occupying the side band HH. within the quantum well, separated by the energy as occupied by the hole of the degree A state of accumulation of holes with a low effective mass m-// is created, and the parts are moved relative to each other accordingly. The thickness of the layer containing the material with a narrow forbidden band is substantially selected so that the conductance increases has been done.

According to a second feature of the invention, it presents a modified structure with respect to conventional heterojunctions. Parts are suggested.

In this second feature of the invention, the components are sequentially grown epitaxially on the substrate. In addition, III-V semiconductor materials with a wide forbidden band (AIzGa on GaAs substrate) +−zA　S) and: l11− with a narrow forbidden band. V semiconductor material (Ga, In+-yAsSGaASwSb+-w, or Ga y　I　n　+−yA　swS　b+−w) , III-V semiconductor material with a wide forbidden band (A I x G a + - x A S (preferably), and the crystal lattice mismatch between these layers Therefore, a layer containing a material with a narrow forbidden band is subjected to uniaxial compressive strain in the plane of the layer, and this Forming a quantum well with HH-type sidebands in the valence band loop of the structure at the layer level of Ru. Furthermore, the thickness of the layer containing the material with a narrow forbidden band and the composition of the material with a wide forbidden band have negative effects. When a voltage is applied to the gate, there are sidebands HH1 and HH2 in the quantum well, and in some cases This is essentially chosen such that a higher order sideband HH,102, appears; Among the various side bands, the side band corresponding to the highest effective mass m″kl/occupies the side band HH+. energy that is occupied by holes with a much lower density than that of holes. - Separated by is created and the transconductance of the component increases accordingly. It is.

In any of the features of the present invention, the material with a narrow forbidden band is Ga or In+-vAs. When the thickness of the layer containing this material is such that the hole density within the sideband HH is much lower than the density of (so that the mole fraction of indium (1y)+++ is 0 ．． 15 and 0.35, selected between about 4 nm and about 6 nm, and the side The iE hole density in the band HHs is much lower than that in the side bands HH+ and HH2. uni, when the mole fraction of indium (1y) In is between 0.15 and 0.30 , between about 6 nm and about 9 nm.

The invention further provides that for an n-channel transistor the average effective mass of holes m″h // to lower I and increase the transconductance and its current density accordingly. at least one p-channel field effect transistor fabricated in accordance with the teachings of; p-channel and n-channel field effect transistors, characterized in that they include transistors. It also covers integrated circuits with complementary components of the transistor type.

◇ The invention will now be described in detail with reference to the accompanying drawings. Same in all figures The numbers refer to the same elements.

FIG. 1 shows that the present invention is applied to the structure of p-channel components, respectively n-channel The general structure of two transistors, p-channel and p-channel, is shown.

2a, 2b, 2c show the conduction band and valence band states for the structure of FIG. quiescent state, positive gate voltage applied (for n-channel transistor) and negative gate voltage, respectively. (in the case of an n-channel transistor).

Figure 3 shows the energy as a function of the wave vector for a material with no pressure. The valence band diagrams of GaAs and GaInAs are shown in the case of FIG.

Figure 4 schematically shows the structure of a stressed heterojunction and the nature of the applied pressure. ing.

FIG. 5 is a view similar to FIG. 3 of the stressed material of FIG. 4;

116a and 6b are static structures with a pressured structure containing a small amount of aluminum, respectively. It shows the valence band state in the stopped state and with a negative voltage applied to the gate.

Figures 7a and 7b are similar diagrams to Figures 6a and 6b, except that the structure has a higher aluminum content. It is.

Figures 8a and 8b show the level of the GalnAs layer, which is made with two different thicknesses. The figure shows the shape of the quantum well formed in this case.

Figures 9a and 9b show the vias for two different negative voltages on the gate. This is shown in Figure 8b, which specifically takes into account the triangular deformation of the quantum well when multiplied by This shows more clearly the location of the different sidebands that exist within the quantum well.

Figures 10a, 10b and 10c respectively show the static state for the case of the prior art structure. The state of the valence band when two different negative voltages are applied to the state and the gate. , as well as the quantum well and the sideband states appearing within this well.

11a, llb, llc are for the structure according to the first feature of the invention, FIG. 10a 110b, a diagram similar to LoC.

FIG. 12 is a diagram similar to FIG. 1 regarding the structure according to the second feature of the invention.

Figures 13a, 13b, 14, 15, 16 show that GaInAs in various shapes It shows the state of the 1itf-well formed in the layer (more precisely, Fig. 13 a, 13b.

15 is according to the first feature of the present invention, and FIGS. 14 and 16 are according to the first feature of the present invention for comparison. ).

◇ The first structure of the invention, schematically shown in FIG. and, - Consists of the same < GaAs or a stack of GaAs/AlGaAs has a thickness of 500 nm. Unless otherwise noted, chemical properties (purity) are typical values listed for reference only. ) and a buffer layer 2 whose crystalline properties are completely controlled; or planar doping (“δ-doping”) 3 and - about 3 nm thick) of GaAs. Layer 4 - 15 nm thick, gallium content yc - about 0.75 to 0.85 (Hereafter, all contents are expressed as mole fractions) G a r I n +- A layer 5 of yA s with a thickness of 25 nm and an aluminum content XAI of approximately 075 a layer 6 of A l x G a + - x As of degree; - protective layer 7 with a thickness of 3 nm: and has.

Incidentally, the upper layer of the AlrInI-rAs layer 6 on the GalnAs layer 5, etc. Group III-V alloys other than the examples given above can also be used, and the content of different constituents may be particularly On the InP substrate, it is chosen to match the lattice constants of the different alloys.

On the other hand, all the layers forming this initial structure are undoped, except for planar doping. This is the ping layer.

On top of this structure, it penetrates up to layer 3, so that it is completely The source, drain, and gate electrodes S, D, and G are formed by n 8 and 9, respectively. n-channel and p-channel by implanting doping areas of and p A field effect transistor can be formed.

In this way n- and p-channel complementary transistor logic circuits can be realized. , as mentioned above, the present invention was conceived to be manufactured separately, i.e., discreetly. It can also be applied in the fabrication of p-channel field effect transistors in the form of flat components.

In the case of an n-channel transistor, a high positive voltage exceeding the threshold voltage Vτ is applied to the gate. When the voltage is applied to A channel is formed. Conversely, in the case of an n-channel transistor, the threshold voltage VT When a large negative voltage lower than I is applied to the gate, the Ga, In+-yAsAs layer Holes are accumulated in the channel, and a p-type channel is formed at this time.

Figures 2a, 2b, and 2c show the shapes of the conduction band Ec and the valence band Ev, respectively in the stationary state. state, positive gate voltage applied (for n-channel transistors) and negative gate voltage (for n-channel transistors). VG is the applied gate The voltage (O1 positive or negative as the case may be), E, represents the Fermi level. 10 is n 11 represents the place where electrons are accumulated in the case of a channel transistor, and 11 is an n-channel transistor. represents the location where holes are accumulated in the case of a channel transistor.

The states of conduction of holes and electrons, which we will discuss below, are very different. In the structures realized to date, n-channel transistors are integrated in the same circuit. An extremely large discrepancy occurs between the characteristics of the transistor and the n-channel transistor. ing.

In fact, electrons in GaAs or GaInAs have a low effective mass m0. and positive The hole is found to have a large effective volume ff1m''h (as mentioned earlier, The effective mass corresponds to the statistical average) 5 In other words, the mobility of electrons is high and the mobility of holes is is very low.

In order to solve this difficulty that hinders the production of high-speed complementary logic circuits, G and C.

0sbourn and others Electron and Hole Effective 　l1asses　forTwo-Dimensional　Transport t in 5 trained-Layer 5 upper lattices, 5u Persecution ≠ Crackling ■■ and Microstructures, Vt+1.1. No, 3. p. , 223 (1985), which utilizes complex physical phenomena outlined below. to create a GaInAs layer under pressure that has the effect of reducing the effective mass of holes. proposed combining Ga1nAs with GaAs or AlGaAs to did.

Moon-, ) Gong (For unrestrained materials, the valence band of GaAs or Ga1nAs The curve is divided into two clearly separated bands. Figure 3 shows the plane (ε, ) shows a diagram of the valence band in (energy represented by a wave function). At HH One of these bands shown is called the "heavy hole band" and the other labeled LH. The band is called the "light hole band." The effective mass of a hole is determined by the following relational expression: It is known that it is inversely proportional to the band curve. m”h=h”/(a’e/θ/C2) (1) In this formula, h is a blank constant, It is known that ε is energy and is a wave vector.

Next, Ga1 sandwiched between two layers of GaAs or AlGaAs shown in FIG. Considering a material under pressure, such as a thin layer of nAs, G in a plane parallel to the interface The layer of a1nAs undergoes compression as indicated by arrow 12, while in the vertical plane it undergoes compression as indicated by arrow 13 is subjected to a tension expressed as

In the corresponding valence band diagram shown in Figure 5, this deformation results in a valence band are separated, and the band is significantly deformed in a plane parallel to the interface.

In Figure 5, the right half of the diagram corresponds to the wave vector parallel to the interface, and the left half corresponds to 7/. corresponds to the wave vector perpendicular to the interface. parallel to the interface (i.e., the right half of Figure 5) ), the band is strongly deformed, the "heavy" holes HH become lighter, and conversely the "light" holes LH becomes heavier, while in the direction perpendicular to the interface (i.e. in the left half of Figure 5), the “heavy” positive Holes HH remain heavy and "light" holes LH remain light. In other words, holes The reversal of the lightness property occurs on one side of the valence band, but not on the other. .

This valence band deformation also changes the statistical distribution of hole filling: for example, on average, G aAs/Ga InAs/GaAs or AlGaAs/Ga InAs/A In the lGaAs system, the effective mass of the hole is the unpressured GaAs/A It is smaller than the mass in the lGaAs system. Therefore, such pressure The mobility of n-channel transistors increases in a system where As a result, mutual conductance g1 is improved. For example, in the above paper by Grider, is the mutual conductance g of a transistor with a gate length of 1 μm. is 70mS /mm (millimeters or millisiemens). deer The thickness value is about 300m5/mm for a similar mutual relationship of n-channel transistors. It is much lower than the value of conductance g-, which is 4.3:1, and the n-channel If you want to make a transistor work like an n-channel transistor, This is a value that must be overcome.

Very recently, B. Laikhtman et al. tuIlfellValence-Band 5structure and 0 ptiIIIal Parameters for AlGaAs-1nGaA sword |AIGaAs p-Channel Field-Effect Transistors, J, Appl, Phys, Vol. 70. No, 3. @p, 1531 (1991), GaInAs contained between two layers of AlGaAs The effective mass of holes is further reduced using quantum wells formed in one region of the layer. However, the composition of these layers and the quantum well width (i.e., G The thickness of the alnAs layer) is set so that the height of HH2 is exactly the height of the thread of the quantum well. must be defined. Figure 9 in this paper shows a very small particle on the order of an electron, i.e. The effective mass, which is close to 0.07 mq (mo is the mass of electrons), is the aluminum content AI is 0. It shows that it is achievable provided that it is 2 or more. same opinion From Figure 8 of the text, the authors recommend using a GalnAs layer with a thickness between 2 and 5 nm. However, when the thickness value is the most important, aluminum concentration Degree X^1 is the lowest.

To be more precise, XAl=0.2 is the thickness of G a v 1 n 1 - y A s XAl=0.8 corresponds to a thickness of about 4 to 5 nm, and XAl=0.8 corresponds to a thickness of 2.5 nm for Ga, In+-, As. It corresponds to about 5 nm.

However, this structure is not suitable for both low and high aluminum content. They are facing all sorts of major obstacles.

This is because when the aluminum content is low, the structure becomes less discontinuous in the valence band. In other words, the potential barrier ΔE is low. For the ias time (Fig. 6b), the valence electrons of such a structure, where X^, = approximately 0.2 The outline of the obi is shown. In this case of negative bias, ΔE, is lower than O,IV. , with such a low barrier, the holes will experience tunneling effects (arrow 14 in Figure 6b) and/or or the barrier is crossed by the thermionic effect (Fig. 15). Tunnel effect and heat The on-effect produces so large a gate leakage current that the transistor is stop working.

On the contrary, a structure with a high aluminum content (XAI≧about 0.7) has a potential barrier ΔE, However, as shown in Figures 7a and 7b, it becomes quite high, about 0.4V or more, and the tunnel The height is high enough that the leakage current due to the effect can be ignored. However, this result In order to According to the paper, the indium content (1y)+-≧0.25 is 2.5 nm. Must be reduced to a low value.

Such a thin thickness presents several problems, not least of which is the small thickness of m; In space, a hole (or electron) has severe interaction with the two interfaces that confine it. On the other hand, AlGaAs and Ga The actual conditions for crystal growth of InAs layers are very different, so that perfect quality interfaces cannot be obtained. It becomes very difficult to obtain the However, it decreases further when the width of the quantum well is small.

Thus, the prior art teaches that it increases hole mobility, but When the purpose is to increase the mutual conductance of an n-channel transistor, In reality, we reach a dead end, but it is because the aluminum content is too low. Large leakage currents occur and high aluminum content makes the layer too thin to be effective. This is also because it will not be possible to manufacture the product properly.

The aim of the invention is to overcome all of these limitations and to ensure that e.g. Very large transconductance, as high as an n-channel transistor The purpose of this invention is to make it possible to fabricate a thin n-channel transistor.

This can be achieved in two ways as described below, one of which is the conventional structure of quantum wells. The other is the one that changes the structure to further improve the performance. be.

First embodiment of the invention The present invention includes A I x G a 1-XA 8 layers 6, G a, I n As shown in FIG. 1, it has a quantum well formed between the S layer 5 and the GaAs layer 4. Use a basic structure.

The physical effects that act on these layers are -Position and shape of valence r/band and plane of layer 5 of G a v I n +-yA s and the effect of mechanical pressure acting on the effective mass of holes in a plane parallel to this, - 1 in the thin film 5. 7t-r- Appearance of lateral band (level), -A I x G a + - x A 8 layer 6 This is a tunnel effect that passes through a potential barrier made up of.

In addition to these three effects, there are also effects related to the width of the quantum well, i.e. 　v　　　n　　　　+-yA　Restrictive consideration regarding the thickness of the s layer 5 is added.

As demonstrated ((in this regard, a detailed description of this phenomenon by the applicant) , see French patent application No. 91-15140 describing In the case of channel transistors, the aluminum content increases due to the tunneling effect experienced by electrons. This last parameter (quantum well width).

First, as a first approximation, the quantum well made by Garln+-+As is Assume that it is symmetrical, as shown in Figure 88.8b. Inside this well, there is a quantum sideband HH ,.

EH2, EH3, etc. appear, but as shown in Figure 8, the width of the well is small. The more energy is separated, the more energy is separated. Lateral band LH, LHz energy The level is such that, as in this case, the indium content (1y)+- is 0. If it exceeds 2°, it is very far from the valence band peak (greater than 150 mV). ), so the involvement of holes LH can be ignored. Therefore, these side bands are transistor Under normal conditions of operation, it is not occupied by holes.

The effective mass IILm”h// in the plane parallel to the interface of holes HH2, HHs, etc. is the hole It is known that it is larger than that of HHI. Therefore, the lateral bands HHt, HHs For example, it is advantageous to have as few holes as possible. La i kh tman As shown in Figure 8b, the above-mentioned paper was designed so that the side band HH2 is located just at the edge of the well. proposed using sufficiently narrow quantum wells, resulting in widths of around 2.5 nm. It becomes a well of degrees. However, this condition is neither necessary nor 1 minute.

On the other hand, as mentioned earlier, due to the hole tunneling effect through the potential barrier ΔE, This condition was not sufficient when the aluminum content X^1 was low. This is n In the case of channel transistors, aluminum is used due to the fear of tunneling effect caused by electrons. The nium content X^1 is about 0. It means 7 or more. However, this condition In order for ΔE to exceed 500 mV and the level HH2 not to be filled with holes, It is not necessary that this level be at the edge of the well, i.e. at the bottom of the well; it is just H The side band HHI is sufficiently far away so that the ratio of hole densities in Ht and HH can be ignored. It is necessary to

If the negligible limit for this ratio is a few percent, then the holes in the sideband HHf between HH+ and HHt so that the density is a few percent of the hole density in the sideband HH, The difference in energy levels can be determined.

The hole density p changes depending on the energy level EH of the side band according to the following relational expression: It is known that

p=Nveexp [-(EH-EF)/kT], (2) and Nv=m”, 〃kT/πh’ (3) Here, EF is the Fermi level, k is Portzmann's constant, T is the absolute temperature, and h is the Brass constant. The link constant, m″h//, is the effective mass of holes.

, 11p, -1, condition (the hole density of HH2 is several percent of the hole density of HH, cents) is satisfied when the level HH2 differs from HH+ by about 125 mV. The width of the clear f-well at that time was approximately 5 nm, and this value was determined by Laikhtman. The value of 2.5 nm is much higher than 1, which is recommended by the authors.

More precisely, in the hole accumulation state (i.e., Vc≦about-1■, the gate is strongly L) when a bias of fs is applied), the shape of the quantum well is not rectangular and is shown in Fig. a.

It becomes a pseudo-triangle as shown in 9b.

Under this condition, the energy to separate the sub-levels HH and HH2 is higher than in the case of a rectangular shape. is also slightly higher, but this variation is negligible for a difference value of 125 mV.

However, the shape of the pseudotriangle becomes extremely important when the quantum well is not symmetric. ri, this -1 is L3 i l (htman has not considered it, but Glide r is found in the paper described by Fiij, and its accompanying information is shown in Figures 2a to 2 for reference. Explained in C.

Figures 10a, 10b and 10c are shown for gate voltage 0 and two increasing negative gate voltages, respectively. Regarding the gate voltage, the valence band diagram in this case is described in more detail.

The valence band discontinuity ΔE between Ga, In+-vAs and GaAs is 0.25 80 to 13 according to the indium concentration (1y) +- varying from 0 to 040 It can be seen that the voltage is about ゜nlV. Furthermore, in the equilibrium state (Fig. 10a), the well The three quantum sidebands HHI, HHt, HH are calculated by taking into account the larger width (15pm). It turns out that s exists. At equilibrium, this well is not filled with holes, but When the gate voltage is high enough (Fig. 10b), the band curve becomes a large number of quantum sidebands HH+, Pseudo-triangular wells appear with the presence of HHt, HHs, EH4, and HH5. Fe Considering the energy positions of these side bands with respect to the Lumi level and the HH+ level, Therefore, the sideband HHL, and especially the sideband) (H3 is filled with holes. However, M. Jaffe et al., Theoretical Formalism to U derstand the Role of 5train in the T≠Attack shield nitsakushi■ of Bole Masses in p Type InxGa+-xAs (on GaAs 5ubstrates) andInOsx, xGao +y -JS (on InP 5ubstrates) Mtxiulation- Doped Field-Ef■■Mo■ Transistors, Appl, Phys, Lett, Vol, 5 1. No, 23. p, 1943 (19B?) A or As explained by Laikhtman in the above-mentioned paper, the upper lateral band HH2 and The effective mass of the hole in HH, is much higher than that in the side band HH+, and the mass ratio is It can increase up to 10 times.

Taking into account the filling statistics of levels HH+, EH2, HH3111, Jaf According to fe, the average effective mass of holes m''hii of about 0.324mo is calculated. , this value is 48 times the effective mass of TL'I'.

This results in an n-channel transistor transconductor of 70m5/mm. This value agrees with the experimental results obtained in the 300 m5/mm This is 1/4.3 of the value for an n-channel transistor.

As we proved earlier (this obstacle is overcome by the use of quantum wells with a width of about 5 nm). It will be done.

Figures 11a to llc illustrate the width of quantum wells according to the invention in Figures 10a to 10. c, and shows the state of the corresponding valence T-band.

In the equilibrium state (Fig. 11a), the amount P well narrowness and Δ between GaAs and Ga1nAs E, due to the combined effect of the low value of about 100 mV, only lateral band HH1 exists. It turns out there isn't. When a sufficient bias of about -1V is applied to the gate (Figure 11b) , a side band HH appears on the band curve. Since the quantum well is narrow, the latter is about HH, 100 millivolts apart (on the contrary, when the quantum well is wide, e.g. Glide At 15 pm, as in the case of (There is only a 0 mV difference and it is filled by a hole with a large effective mass). bias value When is higher, e.g. when vG = about -1.4V (Fig. 11b), the lateral band HHs It may appear, but its level is similar to the level of HH, Fermile. Since it is far enough away from Bell Ep, when the quantum well is narrow enough, it is filled with holes. Not done.

In this way, even when the quantum well is asymmetric, by reducing this width (general (width 5 nm) without filling the first side bands HH, L, and diluting the other side bands (width 5 nm). Can be done. Roughly speaking, when the width of the quantum well is 5 nm, the n-channel transistor The detector only works with holes, which have a small effective mass.

The value of this effective mass increases as pressure is applied to G a y I n + - y A s layer 5. , that is, the higher the indium concentration, the smaller it becomes. However, this pressure exceeds a certain limit. I know that I should not exceed it, and if I exceed it, Gayln+-vAs / G　a　As　layers (layers 5 and 4) and Ga+In+-+As/AlxGa+-xAs Dislocations occur at the interface between the layers (layers 5 and 6).

In fact, this phenomenon depends on the thickness of the G a v I n + - y A s layer 5 (e.g. For example, J, W.

Matthews and A, E, Blakeslee's J, Crystal, Gro wth, Vol. 27°p. 118 (1974)). This layer is thin The more the indium content increases, the more effective the holes occupying the side band HH become. The amount becomes smaller. When the thickness is 5 nm, the indium content (1y)+- is approximately 0. 35, then the effective quantity of holes of level HH, ff1m'', /7 becomes about 0.07 mo, which is approximately the effective mass of an electron.

The difference in energy level between HH, and HH2 increases with indium concentration, but Therefore, this characteristic may promote a decrease in the hole density in H H2 with respect to HH, I understand.

When the effective quality Mm'', /7 is about 0.07mo, the n-channel transistor has n It exhibits mutual inductance similar to that of a channel transistor. At this time, G a v I n + rA s The thickness of the layer 5 is about 5 nm, and when XAI≧about 07 ( 1y) +-≧approximately 0.25 heterojunction AlxGa+-xAs/Gal, In+- Complementary transistor integrated circuits paired in this way can be fabricated using yAs, but It is faster than anything fabricated so far, where the thickness of this layer is about 15 nm. .

In this way, when the thickness of layer 5 is 5 nm, the n-channel transistor has almost no holes. It only works with HH. Similarly, an n-channel transistor has electrons in the sideband E+. only operates at: sideband E2, located 170 mV from E1, is very dilute. .

The hole concentration in HHr is limited by the density of states in this sideband, and similarly in E1. Electron density is also limited. Free carriers (holes in the case of n-channel transistors) , electrons in the case of an n-channel transistor) The current density is therefore such that only the sideband HHI is filled with holes and the sideband E is filled with electric charges. When it is filled with children, it is limited. Therefore, the low effective quality ff1m″h// and the positive A compromise will be found between high concentrations of holes (and electrons). From this point of view , without any filling of sideband HHs by holes with much higher effective masses (7 to 10 times). By eliminating the n-channel transistor, the effective quality is almost two to three times higher than that of the sideband HH. It is permissible to have a sideband HHt filled with a large amount of holes. In this case, Ga The quantum well width of InAs is HH3 and HH3 when the difference between HH2 and HH is about 40 mV. The energy difference between HH+ is chosen to be greater than 125 mV. This condition is This is sufficient for quantum well widths less than about 9 nm: with this quantum well width, the sideband E2 is 50 mV from El, and when a strong bias is applied to the gate, the electron to allow it to be charged. However, as the layer thickness increases to 9 nm Therefore, in order to prevent the appearance of interfacial dislocations, the indium content of this layer must be lowered. Therefore, the indium content (1y)+- is 0.25 to 0.30 Reduce it to a certain degree.

On the other hand, as mentioned earlier, III-V alloys other than those mentioned in the example described can also be used. It is possible, and the contents of various constituents can be specially tailored to suit the lattice constants of different alloys. selected as follows. For example, base 1 that allows you to consider the following structure: In P Layers 2 to 4: A Ir I n+-r As with X'AI = 0.48 and match the lattice constant with INF.

Layer 5: Ga+Ir+ with a mechanical pressure of about 0.12 to 22 +-yAs Layer 6 A　Ir　I　n+-r　As with matching lattice constant Second embodiment of the present invention FIG. 12 schematically shows the basic structure used in the second embodiment of the present invention.

This structure is similar to the first embodiment (the Gayln+-rAs layer with a narrow forbidden band is forbidden). Combined with a wide band A It is not a conventional binary structure with a heterojunction (epitaxially grown on a board). (, wide forbidden band A I x G a + - x A 3 layer 6 and A l z G a +-zA 8th layer 16 and narrow forbidden band sandwiched between the two layers Gaylr++- It has a ternary structure consisting of yAsAs layers, and these three layers are placed on GaAs substrates 1 and 2. It is epitaxially grown. The structure thus obtained is shown in Figure 12. , the same numbers as in Figure 1 indicate similar parts, so no further detailed explanation will be given. .

Next, we will explain the reason for this modification and the advantages compared to the first embodiment of the present invention. I will clarify.

For this reason, it is formed in the valence band with a gate bias Vc of about -IV. Reference is made to FIGS. 13-16, which zoom in on the wells.

FIG. 13a is actually an enlarged view of FIG. 11b, and in a first embodiment of the invention, 5 In the case of a well of about 5 nm, 1i; at the bias voltage mentioned in 1, the sideband HH2 is i Unless the nium concentration (1y)+n reaches approximately 0.35, approximately This shows that it does not exist at 100 millivolts.

However, especially if the difference in lattice constants is very large, metallurgy becomes difficult ( 1y)+n=approximately 0635 Gayln+-, the production of the As layer is quite difficult.

Therefore, a structure with a Garln+- and As layer with a low indium content may also be considered. It will be. However, G　y　I　n　+-rA　s with low indium content If the material has the same quantum well width, as shown in Figure 13b, for example (1y)+-= At 0.20, the level of side band HH2 approaches the level of side band HH, so Ga The discontinuity of the valence TLr band between As and Gayln+-yAs is now 65 mV. ・Under this condition, the hole concentration in HH, and even in HHs can be ignored. and become unable to do so.

To overcome this limitation, the present invention in a second embodiment replaces GaAs. By using a material with a wide forbidden band such as A1□Ga12As, the discontinuity in the valence band can be reduced. We propose to raise the side bands HHt and HH3 to the highest energy. Ru.

Such A I x G a 1-XA s/Ga, I n I-yA s/ The valence band diagram of the Al zGa+-zA s system is shown in FIG. capacity As can be easily seen, even when the concentration of indium is low, A If the aluminum concentration ZAI of A S is sufficiently high, for example 2^+=0.30, G Valence band discontinuity between aylr++-yAs and A IzG a +-zA S The continuity has become sufficient, and the hole concentration between the side bands HH2 and HHs can be ignored. Become.

In this way, in the second example, the indium content is not a critical parameter at all. , the Garln+-rAs layer has a low indium content, which is much easier to metallurgically process. You can choose different materials.

In addition to the indium content of the G a r I n 1-yA s layer, the width of the quantum well The layer thickness, which determines the can do.

In fact, the bias is always VG--IV and the quantum well width is about 6 to 9 nm. In Figure 15, which shows the valence r-banding of the actual h & example, the side band HH2 is HH, about 5 0 mV and the sideband [(H3 is the expansion of the quantum well, as in the previous case in Fig. 13a). Mostly within.

However, this sideband HH3 is 40 to 80 mV from HH2 (quantum well Depending on the depth of the door, the indium content must be between 0.025 and 0.30. j rate (1y)), yet this sideband ignores its hole concentration It's still too close to HH7 for that.

In order to overcome this constraint, AI was used instead of GaAs as in the case of FIG. Using a material with a wide forbidden band, such as zG a 1-zA S, as shown in Figure 16 As shown in FIG. Regardless, pushing the sideband HH from HH2 to at least 100 mV Can be done.

Here too, the aluminum content C1 of A　I　G　a　+-zA　S is important For example, ZAI>0.15.

It should be noted here that the alloy composition mentioned above is not limiting (especially in the central thin layer). Therefore, it is possible to advantageously use alloys other than Ga and I old-yAs. be.

For example, antimony-based materials have higher hole mobility than Ga, Ir++-rAs. There is an alloy. In this respect, the compound GaSb has a lattice constant similar to InAs, so , GaAswSbl-w (w is about 0.85 to 0.90) and Gavlnl- yAswsb+-v (y is about 0.70 to 0.80, W is about 0.85 to 0 90) alloys will also be subjected to uniaxial stress due to compression.

F (GjOa FIG-11a Continuation of front page (51) Int, C1,' Identification symbol Internal office reference number HOIL 29106 8427-4M29/66 8427-4M 9171-4M (81) Designated countries EP (AT, BE, CH, DE.

DK, ES, FR, GB, GR, IE, IT, LU, MC, NL, PT, S E), JP, USI HOIL 29/80 E

Claims (10)

[Claims] 1. III, which has a wide forbidden band in p-channel field effect transistor type components - due to the crystal lattice mismatch between the layer (6) containing the V semiconductor material and the rest of the structure. The forbidden zone is a narrow forbidden zone in which a layer containing a material is subjected to compressive uniaxial pressure within the plane of the layer. has a heterojunction formed between layers (5) containing narrow III-V semiconductor material; , this heterojunction is a layer containing a material with a narrow forbidden band in the valence band diagram of the heterostructure. A component that forms a quantum well that creates an HH type subband at the level, When a negative voltage (VG) is applied to the gate, subbands HH1 and HH2 are created in the quantum well. , and possibly higher order subbands HH3, . ．． ．． is essentially selected so that The subband of these famous species is the subband corresponding to the highest effective mass m h//. The hole is occupied by holes at a much lower density than the holes occupying HH1. accumulation of holes with low effective mass m h// in the quantum well separated by energy A condition is created that inhibits the mutual conductance of the components to increase accordingly. Part characterized in that the thickness of the layer containing the material with a narrow band is substantially selected . 2. Component according to claim 1, in which the material is epitaxially deposited on a substrate (1) of GaAs. AlxGa1-xAs is a sial-grown material with a wide forbidden band, and the forbidden band is narrow. A component characterized in that the material is GayIn1-yAs. 3. Component according to claim 1, characterized in that the material is epitaxied on a substrate (1) of InP. Al-grown material with a wide forbidden band is AlxIn1-xAs, and the forbidden band is narrow. A component characterized in that the material is GayIn1-yAs. 4. In components of the p-channel field effect transistor type, - successively the substrate ( 1) Epitaxially grown on: Contains a III-V semiconductor material with a wide forbidden band a first layer (16); a layer (5) containing a III-V semiconductor material with a narrow forbidden band; ・A second layer (6) containing a III-V semiconductor material with a wide forbidden band; A layer containing a material with a narrow forbidden band due to the crystal lattice mismatch between the layers is compressed in the plane of the layer. Under the pressure in the uniaxial direction, an HH-type subband is created in the valence band diagram at the level of this layer. form a quantum well, −The thickness of the layer containing the material with a narrow forbidden band and the composition of the material with a wide forbidden band have a negative effect on the gate. When a voltage (VG) is applied, there are subbands HB1 and HH2 in the quantum well, and in some cases Therefore, the higher order subbands HH3, . ．． ．． or essentially selected to appear, this Among the various sub-bands, the sub-band corresponding to the highest effective mass m h// occupies the sub-band HH1. energy that is occupied by holes with a much lower density than that of holes. The accumulation state of holes with low effective mass m h// is separated by selected such that the transconductance of the components increases accordingly. Parts characterized by: 5. 5. A component according to claim 4, wherein the material is epitaxial on a substrate of GaAs. The grown second layer material with a wide forbidden band is AlxGa1-xAs, and the forbidden band is The material with a narrow forbidden band is GayIn1-yAs, and the material with a wide forbidden band in the first layer is Al. A component characterized by being zGa1-zAs. 6. A component according to any one of claims 1 or 4, characterized in that the material has a narrow forbidden band. A component characterized in that is GaAswSb1-w. 7. A component according to any one of claims 1 or 4, characterized in that the material has a narrow forbidden band. or GayIn1-yAswSb1-w. 8. Component according to any one of claims 2 or 5, wherein GayIn1-y The thickness of the layer containing As is such that the hole density in the subband HH2 is greater than the density in the subband HH1. The mole fraction of indium (1-y)In is 0.15 and 0.3 so that it is very low. 5, the wavelength can be approximately included between about 4 nm and about 6 nm. parts. 9. Component according to any one of claims 2 or 5, wherein GayIn1-y The thickness of the layer containing As is such that the hole density in subband HH3 is the same as the density in subbands HH1 and HH2. The mole fraction of indium (1-y)In is much lower than 0.15 and 0.30, it can be included approximately between about 6 nm and about 9 nm. Parts featuring: 10. Lowering the average effective mass of holes m h // for p-channel transistors , any of the above so as to increase the transconductance and its current density accordingly at least one p-channel field effect transistor made according to the claims of p-channel and n-channel field effect transistors, characterized in that they include An integrated circuit with complementary components of the type ta.