TW493224B - Composite doped channel heterostructure field-effect transistor - Google Patents

Abstract

A composite doped channel (CDC) heterostructure field-effect transistor (HFET) for high- performance applications is disclosed. The key figures of the proposed device in this invention are illustrated as follow: (1) The n<SP>+</SP>-In0.2Ga0.8As/n-GaAs layers form the CDC structure. The narrow InGaAs layer is used to introduce the channel quantization effect. Thus, the effective energy-gap of InGaAs layer can be increased. The n-GaAs channel can improve the operation capability under higher electric field. Hence, the impact ionization effect can be avoided and the leakage current is minimized. (2) The undoped wide-gap In0.49Ga0.51P (~1.92 eV) material is used as the Schottky gate and buffer layer. The upper In0.49Ga0.51P layer can provide good Schottky characteristics. The lower In0.49Ga0.51P layer is used to suppress the substrate leakage current through the substrate leakage path to provide good pinch-off characteristics. (3) The large conduction band discontinuity (ΔEc) at the In0.49Ga0.51P/In0.2Ga0.8As and GaAs/In0.49Ga0.51P interface can provide better carrier confinement in the channel. Therefore, the proposed device still has good performances even at high temperature regime.

Description

493224 V. Description of the invention (1) Field of the invention The present invention relates to a composite doped channel heterostructure field-effect electric crystal 'which can still maintain good element characteristics in a high temperature environment. BACKGROUND OF THE INVENTION Because indium gallium arsenide (InGaAs) materials have the advantages of lower effective mass, relatively high mobility and saturation speed, etc., in order to obtain better device enablement, gallium arsenide (GaAs) is used as substrate heterogeneity In the structure field effect transistor, it has become a trend to use indium gallium arsenide (InGaAs) instead of gallium arsenide (GaAs) as a channel material. However, due to the small energy gap of indium gallium arsenide (InGaAs) materials, impact ionization effects will occur under high electric fields, which will cause degradation of device characteristics including leakage current, breakdown voltage, output conductance, voltage gain, and temperature performance. . The inventor of this case and his collaborators disclosed in Chinese Patent Gazette Bulletin No. 452978 or Patent Case that a high breakdown voltage heterostructure field effect transistor capable of withstanding high temperature operation, including a semiconductor substrate; a buffer layer on the substrate surface, A single-atom doped layer on the buffer layer; an undoped layer on the single-atom doped layer; a secondary channel layer on the undoped layer; a primary channel layer on the secondary channel layer; A gate layer on the main channel layer; an ohmic contact layer on the gate layer. SUMMARY OF THE INVENTION The main object of the present invention is to provide a field effect transistor of a composite doped channel heterostructure without the disadvantages of the foregoing prior art. s

493224 V. Description of the invention (2) '' ~ ------, A composite doped transistor completed in accordance with the present invention, including: &quot; shell, silicon, and semiconductor structure; a semiconductor substrate; A buffer layer on the surface of the substrate—]; a buffer layer-2 on the buffer layer-1; a doped channel layer-1 on the rhenium buffer layer-2; and a buffer layer-2 on the doped channel layer-1 A doped channel layer-2; a photky contact layer on the doped channel layer-2; an ohmic contact on the schottky contact layer; a portion of the base contact layer is exposed to the ohmic contact layer He Suite a drain and source located on the ohmic contact layer; and an exposed transistor located on the Schottky contact layer, the substrate "; Thickness: 9 仏, 仏, 铟, 铟 (InG49GaG, 1P), 1 is the right buffer layer-2 is undoped; ^ 痄 · # r · ΰ1 It has a dry range between 200 ~ 50 With a degree of 0 angstrom, the buffer layer -2 may also be undoped, and its thickness ranges from 200 to 500 angstroms, while Cao X Baxuan, · 豕 lxGai_xAs), 〇 · 2 ~ 1 · 0 The buffer layer-2 can also have a variation range of ΓΛ1 τ ^ force J is undoped indium aluminum phosphide ul 0.55G 5P) 'its thickness range is 2 series gallium (GaAs), which has a thickness of two 52 °; γ ′ channel channel-1 ^ η = 1χ10π.6χ1〇1δ cm-3 ^ n ^; f50'300 ^ ^ Layer 1-2 series doped indium gallium arsenide (InGa (d〇pant), The doped channel has a thickness of 30 to 300 angstroms and a Mohr fraction X of which the thickness ranges from 0.05 to 0.3 in the quarter and the concentration ranges

493224 __90126084 Rev. 5th, the description of the invention (3) at n = lX1017 ~ βχι〇ΐ8 (: 11 type dopant of {11-3; the Schottky contact layer is undoped with phosphating Indium, which has a thickness ranging from 100 to 100 angstroms; the Schottky contact layer may also be undoped gallium arsenide chain (AlxGai_xAs), which has a thickness ranging from 100 to 100 angstroms, The variation range of the Mohr fraction χ is from 0.2 to 1.0. The Schottky contact layer can also be formed of an undoped τ stone-chemical steel (Ai ^ In. /) Material, and its thickness range is 100 ~ 100 Angstroms; the ohmic contact layer is doped with gallium arsenide (GaAs), which has a thickness ranging from 200 to 500 Angstroms, and the concentration range is n = l X low ~ 1 X 1〇i9 cm-3 n-type doping. Alternatively, in the transistor of the present invention, the substrate is a semi-insulating indium phosphide (InP); the buffer Layer-; 1 is undoped hafnium phosphide (InP), the thickness of which is in the range of 0. p5 0 # m; the buffer layer 2

Jtn Un == Kunhua Indium Ming Ul ° .48ln ° .52As), which has a thickness in the range of ^ 00 ～ 〇000 angstroms; the buffer layer-2 may also be undoped antimony arsenide aluminum ^ IrVxASySlVy), which has a thickness in the range of 50000 Angstroms, and the Mo's S :: x®'s 1 'consumption range is 0.3 0.6, and the range of y is 0.7 ~ hO; the S i; I i Dish indium (InP) material is formed, which has a thickness range of 畜. Two animals: S 'Chendu dry around n = 1 Xl〇17 ~ 6 Xl〇1S cnr3 n-type doped also' ... kthis a-2 series Doped with indium ammonium arsenide (j A s), rhenium with a severity range of 30 to 300 angstroms, and concentrated production of r 円 —0.53 Ga 0.47 As), with, and erbium-type doping; the channel layer is surrounded by n = 1X1 (F ~ 6X1018 ... finely formed, which has a thickness of 4: 3 is 〇 = Kunhua 锢 Gallium Ⅰ) Material circumference is 0.3]. 〇, the concentration range is 10 ~ 50 Angstroms, Molar fraction Variation of X. Miscellaneous I I n-type doped at η -1 χ 1 〇17 ~ 6 X 1 018 cnr3 ^ Tecki contact layer is not doped with indium mw% 52As, with

493224 V. Description of the invention (4) &quot;-* 1. The thickness ranges from 100 to 100 Angstroms; the Schottky contact layer may also be undoped antimony dioxide, aluminum (AlxIUSySbh), which has a thickness The range is 100 ~ 1000. The variation range of the mol fraction X is 0.3 ~ 0.6. The range of y is 0.7 ~ 1.0. The ohmic contact layer is doped with arsenide. Indium gallium (InQ53GaG47As) has an n-type doping with a thickness ranging from 2000 to 5000 angstroms and a concentration ranging from η = 1 × 1018 to 1 × 1019 cnr3. Chaya Jiadi 'The gate metal is gold (Au), aluminum (A1), titanium (Ti), indium U0), platinum (Pt), or an alloy thereof, and more preferably gold (Au). The drain and source electrodes are preferably gold-germanium-nickel (Au / Ge / Ni) metal. In a preferred embodiment of the present invention, the device of the present invention has the following characteristics: (1) Two n + 1 1 n0.2. GaGa 8As / n-GaAs composite doped channel junctions are used. (InQ 2GaQ 8As) layer thickness to form the channel amount f = effect, which can increase the energy gap of the InG.2GaQ 8As channel layer, while the GaAs layer can increase the The "working ability" under high electric field can avoid the occurrence of impact ionization, and the leakage current can be reduced accordingly; (2) the use of a large energy gap indium gallium phosphide (InQ 51p) material as the Xiao 1 base contact layer and buffer Layer; the upper InG49GaG5iP layer can provide good Schottky characteristics; the lower InGa9P layer (Inu9GaG 51p) layer can suppress the substrate leakage current from the substrate, so that the device has a good inflammation (Zeng 3) In0.49Ga0 51P / ln () 2Ga〇, In〇49Ga〇5iP / GaAs The large discontinuity of the conduction band between the interface (△ &amp;) can effectively limit the carrier to the compound

493224

It is guaranteed that the element of the present invention has good element characteristics even under a high temperature environment. τ m The composite doped channel heterostructure field effect of the present invention has low leakage current, gastric breakdown voltage, and low electricity, and its performance on temperature is urgent. ^: d !: ΐ line,] this invention The components are widely used in China today: exhibitions and wireless communication systems have great potential. The characteristics and technical contents of the invention can be clearly understood. The following will give a preferred specific embodiment and cooperate with the The drawings are used to explain the detailed description of the preferred embodiment in detail ... Consider Figure 1, which is a composite #heterochannel heterostructure field effect transistor according to a preferred embodiment of the present invention. It consists of a semi-insulating gallium arsenide (GaAs) substrate—12; thick ° 05; undoped gallium arsenide (GaAs) buffer layer-14; 500 angstroms thick; undoped steel (InG.49Ga (). 51P) layer-16; 15 angstroms thick, concentration n = r5> &lt; 1017 gallium arsenide (GaAs) channel layer_18; 50 angstroms thick, concentration η + = 4χ1. 18 cm_3 InuGauAs channel layer—20; thickness 300 Angstroms, undoped disc-formed gallium (In. “Gao S1P) Schottky contact layer—22 ; And a gallium arsenide ohmic contact layer -24 with a thickness of 500 angstroms and a concentration of n + MxlfPcnr3; and then two gold-germanium-nickel (Au / Ge / Ni) metals -26 and -28 were deposited on the gallium arsenide ohm The contact layer -24 and the gold (Au) metal -30 are vapor-deposited on the indium gallium phosphide (InQ49GauiP) Schottky contact layer-2 2 as the source (g urce) and the drain, respectively. Electrode of Drain and Gate.

493224 V. Description of the invention (6) The structure of the device of the present invention is formed on a gallium halide (GaAs) substrate by low pressure metal organic chemical vapor deposition (LP-MOCVD) or molecular beam stupid growth (MBE). Growth income. The device is prepared by conventional wet etching, photo development, and vacuum evaporation processes. Gold-germanium-nickel (Au / Ge / Ni) metal layers -26 and _28 are vapor-deposited on the doped gallium arsenide (GaAs) ohmic contact layer -24, and annealed at about 400 C for 1 minute to Formed an ohmic contact between the source and the source; the gallium arsenide (GaAs) -24 between the source and the source was removed by a coin before evaporation of the gate metal -30 in order to vaporize the gate metal gold (Au) Plated on indium gallium phosphide-22; Finally, the components are isolated by chemical wet engraving. Fig. 2 is a corresponding energy band diagram of the element of the present invention, where &amp; is a conductive band, EF is a Fermi energy level, and Ev is a valence band. In this device, a large band gap indium-gallium (I nQ 49GaG P) material is used as a Schottky contact layer and a buffer layer. The indium gallium phosphide (InGjGauiP) layer above can provide good characteristics of the device; the lower layer of indium gallium phosphide (IiV ^ GauiP) layer can suppress the substrate leakage current leaking from the substrate ^, so that the device has good clamping characteristics. Kunhua 1 Su '~ (In ^ Ga ^ As) and gallium arsenide (GaAs) layers form a composite channel structure. We reduced the thickness of the InG.2GaQ.8As layer to form a flux effect, which can increase the effectiveness of InGaAs (1% sAs) = 2. GaAs layer It can improve the ability of the device to perform fine work under high electric fields. Therefore, the impact-free phenomenon can be avoided and the leakage current is also reduced due to mouth yang. Also in

Shizhihua Steel Record (I n〇49Ga〇51P) and Demichemical Indium Record (I n Q o.2ua0 8As), Shi Yanhua fine Soviet (I η〇.49GaQ 5ΐ Ρ) and Shi Shenhua gallium (GaAs) interface Da Da's Miscellaneous Book> Discontinuity can effectively confine carriers to the channel layer, because μ ^ q can keep the elements of the present invention in a dark, black and western environment. Component characteristics. ° μ clothing

Cut 224 V. Description of the invention (7) Fig. 1 is a graph showing the relationship between the breakdown voltage (Von) of the gate and the temperature of the two ends of the element of the present invention. Gate area and starting of the component. When the gate current is 0.5 mA / mm, the gate breakdown temperature is 100, β, and the temperature is 300, 330, 360, 390, 420, and 450 κ (Vgd) at 23 · 9, 23 · 4, 23 · 0, 22 · 6 and 2 · 0 V; On the other hand:, 4, 5, the starting voltage (Von) is 2. 05, 1. 97, 1. 93, 1. 85, 1 ^ Corresponds to descend v. tl pieces still have a high gate breakdown voltage (By ^ 1.70 voltage (VQn)) at high temperature, and its rate of change with temperature (竽) is 8D and starting X 10 4 / K and 1 · 14 X 10-3 / K. Such an excellent phenomenon proves that the structural design of ^ to 6 · 8 pieces can indeed effectively confine the electrons to the channel layer, invent low leakage current, increase the breakdown voltage, and then increase the component height. Figure 4 This is the characteristic diagram of the two-terminal voltage and three-terminal characteristics of the components of the present invention at different temperatures. The gate area of the component is J χ 100m2. It is the no-sense voltage (VDS), each scale is 2 V; the vertical coordinate is the sink current (ID), each scale is 100 mA / _; the gate-source voltage (vGs) is -0.5 I / step, and the maximum gate voltage is + ι · 5 V. It can be found from the figure that this element has good transistor amplification, saturation, and pinch-off characteristics. Its critical voltages (-) at temperatures of 300, 330, 360, 390, 420, and 450 K are -1.795 '-1.797,- 1.799, -1 · 800, 1.803, and -1 · 808 V. When the temperature increases, the background concentration will increase, which will cause additional leakage current to be lost through the substrate. ' Makes the device's saturation and pinch-off characteristics worse. However, for this device, when the temperature changes from 3 00 K to 450 K, the change in its threshold voltage (Vth) is only 1 3 mV, which indicates the leakage of the device Current can be effective

V. Description of the invention (8): ΐ Low, so that the critical voltage (ν. The rate of change with temperature ㈣, the element of the present invention will be very suitable for digital integrated circuits that need to be accurate and small, so the work pressure (Vth ) The change of electricity is twenty-five. It is equal to t: a; r ;;: degrees are 30 0 and 极, ... pole figure. The second part of the component: == 2 pairs of current ", the relationship 'voltage (VGS), each scale Is 0,5, / m, the nuclear base is the gate-source current per column, and the vertical coordinate is the gate leakage current (IG), / when the temperature is between 300 and 450 κ, Q-source When the pole voltage is in the range of Λ and 22 · t / V, the leakage current (Ig) of the pole is as small as # \ Yue # _. In addition, the general arsenization is not seen in Figure 5. Frequent gate leakage current (D-shaped bell curve, which indicates that the composite channel structure of the element of the present invention can eliminate the impact leakage (impact i〇nizati〇 ^ leakage current is greatly reduced.) Figure 6 is the invention The relationship between the element's transduction value (heart), voltage gain (^), and output conductance (gds) as a function of temperature. The gate area of the element is 1 X 丨 〇〇 // m. The coordinate of the branch is temperature. A scale is 3 κ. The left vertical coordinate is the transconductance value (gm) and the voltage gain (Av). Each scale is 40 mS / mm and 40. The right vertical axis is the output conductance (gds). The degree is 0.05 mS / mm. The bias point of the device is set at a drain-source voltage (VDS) of 6.0 volts and a gate-source voltage (VGS) of +0.5 volts. The output conductance (gds ) 0. 60, 0.61, 0.61, 0.61, 0.60, and 0.60 m S / mm at temperatures of 300, 33, 36, 39, 420, and 450 K. Yes It is found that the output conductance (gds) remains small at high temperatures and has little correlation with the increase in temperature, which proves again

\\ Adm-host \ 20010610 \ P11200 \ ckull299.ptd 493224 V. Description of the invention (9) It is clear that this element can indeed improve the characteristics of the component while maintaining a very low leakage current. On the other hand, the corresponding transduction values (&amp;) are respectively 丨 6}, 丨 5 5, ^ 1 147, H1, and 138 mS / mm, so this component can obtain a phase-to-south voltage gain (A ^ g / gds) values are 268, 254, 248, 241, 235 'and 2 30 respectively. Because the element of the present invention has a relatively high voltage gain value, it is quite suitable for use in amplifier circuits that must be operated at high temperatures. Figure 7 shows the frequency of the element of the present invention between two new elements under different drain current (ID) conditions. The pole area is 1x100㈣2. The horizontal coordinate is the drain package &quot; 丨 L (D), the female scale is 70 mA / mm, and the vertical coordinate is frequency, which coincides with 10 GHz. This component has good frequency characteristics. The maximum early current gain cut-off frequency (unitity cUrrent gain cut-off fre) is 15 9 GHz, and the maximum ^ (maximum oscillation frequency fmax) |, J ^ 3〇. 5 &quot; GHz. On the other hand this The invention element also maintains a wide and linear characteristic. When the operating range of the drain current mA / mm is in Japan, the frequency operation characteristic of this element is kept at its maximum unit only, (fT) and the maximum vibration rate (f_). Above, the stop frequency is quite suitable for the application of high-frequency circuits. Although the present invention has been disclosed as a preferred embodiment, such as ±, autumn is used to limit the present invention 'Anyone skilled in this art, don't leave: :: non Use God and Scope β 'as each Since it is Runxiang, it shall be subject to the definition of the scope of the patent application attached hereafter. The scope of guarantee is on page 14 \\ Adm-host \ 20010610 \ PH200 \ ckull299.ptd 493224 Case No. 90126084 Explanation Figure 1 is a schematic structural diagram of a field-effect transistor of a composite doped channel heterostructure of the present invention. Figure 2 is a corresponding band diagram of the element of the present invention. Figure 3 is a gate breakdown voltage (BVgd) of the element of the present invention and The relationship between the initial voltage () and the temperature. "-Figure 4 is a line graph of the common source current-voltage three-terminal characteristics of the device of the invention at different temperatures. Figure 5 is a device of the invention at temperatures of 30 0 and 450 K. The relationship between gate leakage current and gate-source voltage when the drain-source voltage is 4 and 8 V.

Figure 6 is a graph of the relationship between the transduction value (heart), voltage gain (Av), and output conductance (gdS) of the element of the present invention versus temperature. 'Figure 7 is a frequency characteristic diagram of the element of the present invention under different drain current conditions (D. Figure No. Description 10-Field Effect Transistor 12-Semi-Insulated Gallium Arsenide (GaAs) Substrate 14-Undoped GaAs buffer layer 16-undoped indium gallium phosphide (InQ 49GaQ 51P) buffer layer 18-doped gallium arsenide (GaAs) channel layer

2 0-doped indium gallium arsenide (111 (). 203 (), 5) channel layer 22- undoped indium gallium phosphide (IriG ^ GauiP) Schottky contact layer 2 4 _ Ga A s ohmic contact layer 26, 28-drain, source gold-germanium-nickel (Au / Ge / Ni) 3 0- gate gold (Au)

Claims (1)

493224 Contains: 1 · A composite doped channel heterostructure field effect electricity # a semiconductor substrate;% Ba a buffer layer -1 on the surface of the substrate;-a buffer layer-2 on the buffer layer-1; The doped channel layer on the buffer layer-2 ~ ^; the doped channel layer-2 on the doped channel layer-1-a Schottky junction layer on the doped channel layer-2; An ohmic contact on the Schottky contact layer; a portion of the #based contact layer is exposed to the ohmic contact layer, a drain and a source located on the ohmic contact layer; and The gate of the exposed portion of the Tiki contact layer. The substrate and "2 · The transistor described in item 1 of Shen Qing's patent scope is a semi-insulating gallium arsenide (GaAs). Λ The transistor described in item 2 of the patent scope 'where the buffer is 1 is undoped gallium arsenide (GaAs), which has a thickness ranging from 0 ”m. · 1 ° * 4. The transistor as described in item 3 of the scope of patent application, wherein the buffer layer 2 is undoped indium gallium phosphide (Ι "π), which has a diameter of about 20 0 ~ 50 0 0 Angstrom thickness .. Dry circumference, 5 · The transistor as described in item 3 of the patent application scope, wherein the buffer 6. Shenqing Patent Fanyuan SoHoti Stone AlxGaMAs ′ The thickness range is vector and the variation range of Mohr fraction X is 0.2 ~ 1.0. @ 91 Transistor described in item 3 of the scope of patent application, where the slow balance = ㈣Called plus P), the thickness range · punch # ^, as described in the scope of patent application 4, 5, or 6 transistor Nong Ye ^ 6 two-way force layer ~ 1 series of gallium arsenide (GaAs), which has a thickness ranging from b U to d U ϋ Angstroms, 曲, + +, and 艮 degree range in η = 1 X 1 〇17 ~ 6 X 1 018 c nr3 n-type dopant. / 杂 8 κ ^, s #Kun Ying requested the transistor described in the patent scope item 7, wherein the female-doped line :: tr ((一-一 ^, / ear fraction X changes from 0.05 to 0.3, Concentration range II: η-type dopant with 11J ~ κ x 10 cm · 3. Transistor, where the Xiaofeng P) 'has a thickness range of 9 · As described in item 8 of the scope of patent application 1 Around 100 ~ 1000 Angstroms. 〇 Ｍ 甘 1j · The transistor as described in item 8 of the scope of the patent application, wherein the Xiao = contact layer system is not doped Kuns s), the range is 100 ~ 100 Angstroms, Mohr fraction x The change range is 0.H.0 \\ Adm-host \ 20010610 \ P11200 \ ckull299 • Ptd Page 17 49J224 11. The transistor described in item 8 of the patent application scope, wherein the depression; the circle is 12. The transistor described in item 7 of the patent application scope, wherein the ohmic contact layer is doped with arsenide Gallium (GaAs) has a thickness ranging from 2000 to 5000 angstroms, and an n-type doping with a concentration ranging from PXI 〇 〇 〇 18〜1 XI 〇 19 cnr3. 13. The transistor according to item 1 of the scope of patent application, wherein the drain and source are gold-germanium-nickel (Au / Ge / Ni) metal. 14. The transistor according to item 1 in the scope of the patent application, wherein the gate electrode is gold (Au), aluminum (A1), titanium (Ti), barium (M〇), turn (ρ0 or an alloy thereof). The transistor described in item 14 of the scope of patent application, wherein the gate is gold (Au) metal. 16. The electric body described in item 1 of the scope of patent application, wherein the substrate is a semi-insulating type phosphating Indium (I np). \\ Adm-host \ 20010610 \ P11200 \ ckull299.ptd No. 18 Tribute 493224 6. Application scope of patent Punch layer-1 is undoped indium phosphide (InP), and its thickness range is 0 · 1 ~ 5 · Ο / / m ° 18. The transistor as described in item 17 of the scope of the patent application, wherein the buffer layer-2 is undoped indium aluminum arsenide (Alojs1110.52 ^), which has a thickness ranging from 200 to 5000 angstroms. . 19. The transistor as described in item 17 of the scope of the patent application, wherein the buffer layer-2 is an undoped antimony indium halide (Person 1? (1111- ^ 5 ^^^) 11) ' It has a thickness ranging from 2000 to 50000 angstroms, and a variation range of Mohr fraction χ is 0.3 to 0.6, and a variation range of y is 0.7 to 1.0. 2 0. The transistor as described in claim 18 or 19, wherein the channel layer ~ 1 is doped with indium (I np) and has a thickness ranging from 50 to 300 angstroms and a concentration range. N-type doping at η = ι χ 1 〇i7 ~ 6〆1 〇18 cnr3. 21. The transistor according to item 20 of the scope of the patent application, wherein the channel layer-2 is doped with indium gallium arsenide (In () 53GaQ 47As), which has a thickness ranging from 30 to 300 angstroms and a concentration range. Type 11 doping at η =; ι χ 1017 ~ 6 X 1018 cm-3. 2 2 · The transistor as described in item 20 of the patent application scope, wherein the channel layer-2 is doped indium gallium arsenide (InxGai xAs), which has a thickness ranging from 30 to 150 angstroms and a mole fraction χ The variation range is 0 · 3 ~ 1 · 0, and the concentration range is η-1 X 1 017 ~ 6 χ 1 〇i8 cm-3. \\ Adm.host \ 2001〇61〇 \ pU2〇〇kkull299 ptd Page 19 493224 M5t 90-i2finRd Patent application scope 3 positive / correction / compensation correction transistors, where the Xiao.52As, which has a thickness Fan 23. As described in item 21 of the scope of patent application, the special contact layer is undoped with indium aluminum arsenide. The 48 I n range is 100 to 1000 Angstroms. Temei 2: Touch :: ΐ The transistor described in item 22 of the Scope of Li ', where the Xiao Kun refinement "W-As, which has a thickness ranging from 100 to 1000 Angstroms. The transistor according to item 1, wherein the contact layer is an undoped antimony indium aluminum arsenide (AlxInHAsysb &quot;). 5 The thickness has a thickness ranging from 100 to 100 angstroms. The variation range of the mole fraction χ It is 0.3 to 0.6, and the range of change of y is 0.7 to 1 (). _ 2 6 · The transistor described in item 22 of the patent application range, wherein the Schottky contact layer is undoped with antimony arsenide Inxin aluminum (AlxinixASySbiy) has a thickness ranging from 100 to 10,000 angstroms, a variation range of Mohr fraction X ranging from 0.3 to 0.6, and a variation range of y ranging from 0.7 to ^. 27. The transistor as described in item 20 of the scope of the patent application, wherein the ohmic contact layer is doped with indium gallium arsenide (in ^ 3Ga &quot; 7As), which has a thickness ranging from 20 to 5 000 Angstroms, and a concentration The range is 11 = 1 &gt; &lt; 1018 ~ 1 &gt; &lt; 1019 (: 111-3 type doping of 111-3). 2001.12.21.020