TW441123B - A resonant-tunneling heterostructure bipolar transistor - Google Patents

Abstract

In this invention, we fabricate a new functional resonant-tunneling heterostructure bipolar transistor. In this device, N-AlGaAs, n-GaAs, and n-InGaAs materials are employed as emitter layers. The base layer is grown by an ultrathin p<SP>+</SP>-GaAs layer. Under normal operation mode, the device can exhibit excellent trransistor performances including high current gain, low offset voltage, and N-shaped negative-differential-resistance (NDR) phenomenon simultaneously at room temperature. Due to the insertion of n-GaAs at emitter layer, the potential spike at emitter-base (E-B) junction could be decreased. Thus, the collector-emitter (C-E) offset voltage can be substantially efficiency reduced. In addition, a high current gain is achieved attributed to the use of ultrathin base layer and the reduction of neutral base recombination current. Significantly, the transistor performances incorporating an interesting N-shaped NDR phenomenon are observed under large forward E-B bias at room temperature. That is mainly due to the resonant tunneling of electrons from depleted GaAs emitter (triangular barriers) to collector through the InGaAs quantum well (QW) and ultrathin base layer. Consequently, these properties make the device have a good potential for amplifier, oscillation and logic circuit applications.

Description

4 41 12 3-Λ-Μ〇2572 Correction of the main month and day V. Description of the invention ⑴ ----- Industrial application field The present invention is a new type of functional resonance penetrating heterostructure bipolar transistor, which can achieve high Current gain, low compensation voltage transistor characteristics, and due to the mechanism's resonance penetration mechanism, through appropriate bias, can lead to N-type negative differential resistance characteristics 5 In addition, because of its high frequency performance and heterogeneous interface double The polarity transistor is similar, the component has low noise and the operating frequency can be connected to very high, so it is very significant in microwave applications, such as low noise amplifiers. On the other hand, using the characteristics of N-type negative differential resistance multi-stable state, in addition to being applicable to microwave components such as high-frequency oscillators and frequency dividers, it can also be applied to parity generators and multi-valued logic circuits. Equal digital circuits provide a new direction for the integration of 10 microwave communication circuits and very large integrated circuits in the future. Background Recently, the development of a new type of bipolar transistor with a heterostructure has attracted researchers' high interest. Due to its high-speed and high-current operation capabilities, it has been widely used in digital 15 and microwave power. However, today's integrated circuits are booming, and it is a trend to reduce the number of components' and increase component functions. In the past, researchers at home and abroad have opened

Page 5 441 123-&amp; -M02572- 一 1_ ^ Day five amendments to the invention description (2) '---: --- a practical function type transistor, which also has a transistor in the same component Amplification and negative differential resistance. These characteristics can actually be applied to the multi-stable logic circuits and oscillators of the amplifier circuit. 5 Know-how In recent years, the inventor has successfully developed a variety of functional transistors, such as A1GaAs / GaAs-type heterostructure emitter bipolar transistors (HEBT), in 1995 EE Trans · Electron Device, Volume 42 Reports on InGaP / GaAs type HEBT, pages 1210-1215, IEEE Trans. Electron Devices, 1992, Vol 39, pages 2214-2219, reports AlGaAs / GaAs dual heterostructure emitter bipolar transistors (DHEBT) and AlGaAs / lnGaAs / GaAs-type heterostructure emitters and heterostructure base bipolar transistors (Shenai et al. This type of heterostructure emitter bipolar transistors (HEBT) has a homogeneous emitter layer, so it interfaces with traditional heterogeneity Compared with the double carrier transistor (HBT), it can effectively reduce the offset voltage; 15 At the same time, this type of heterostructure emitter bipolar transistor has a small number of carrier confined layers with a large energy gap, so it can maintain high current Gain, but none of these components have N-type negative differential

Page 6 441123

The resistance characteristics cannot be used for multi-functional applications. The inventors first developed and completed a novel functional aluminum gallium arsenide / aminated / kunhua indium-gated resonance penetrating heterostructure bipolar transistor. Utilizing a very thin base layer, 5 AlGaAs / GaAs / InGaAs heterostructure emitters and InGaAs quantum wells, etc., which make them have large current gain, low compensation compensation, and N-type negative differential resistance in normal operation mode . In addition, this component is simple to manufacture, stable in characteristics and can be operated at normal temperature, which will help to improve the semiconductor process technology at home and abroad, and is suitable for industrial production. 0 The object of the present invention is to develop a new type of functional resonance penetrating heterostructure Bipolar transistor. In forward operation mode, the transistor can simultaneously exhibit the characteristics of large current gain, low compensation voltage, and N-type negative differential resistance at room temperature. Adding gallium palladium in the emitter layer can reduce the compensation voltage between the collector and the emitter. The use of a very thin base layer can reduce the composite current in the neutral base region, so high current gain can be obtained. Under a large base-emitter bias, N-type negative differential resistance can appear under transistor characteristics.

Page 7 441123 ___Case No. 89102572. Month 9 -___ V. Description of the invention (4) These characteristics can be applied to amplifier circuits, oscillators and logic circuits, etc. &quot; To further understand the characteristics of the invention and Technical content 'Please refer to the accompanying drawings and detailed description of the present invention. Those skilled in the art will undoubtedly know the objects and advantages disclosed by the present invention after reading the following detailed description of the preferred embodiments shown by different diagrams. However, the accompanying drawings are provided for reference only and are not intended to limit the present invention. 10 Detailed Description of the Invention The present invention discloses a novel functional resonant penetrating heterostructure bipolar transistor (10). As shown in FIG. 1, it includes: a substrate, a buffer layer, a collector layer, a base layer, A substrate, an emitter layer C, an emitter layer B, an emitter layer A, and an ohmic: I5 contact layer. Among them, a substrate (12) is formed of gallium arsenide (GaAs) material; a buffer layer (U) is formed of gallium arsenide material; a collector layer (16) is formed of gallium arsenide material; A base layer (18) is formed of a gallium halide material; an emitter layer C (20),

4 4112 3-To 02572 __year month day __ 5. Description of the invention (5) &quot; is made of Indium Gallium (In ^ Ga ^ As) material; an emitter layer B (22) is made of arsenic GaAs material is formed; an emitter layer (24) is formed of aluminum gallium arsenide (Al0.45Ga0.55As) material; an ohmic contact layer (26) is formed of gallium arsenide (GaAs) ) Material formation. Its structure is from bottom to top: n + -type arsenide (GaAs) substrate; gallium arsenide (GaAsM 5 layer); gallium arsenide (GaAs) collector layer; gallium arsenide (GaAs) base layer; indium arsenide Gallium (Ii ^ Ga ^ As) emitter layer C; gallium arsenide (GaAs) emitter layer B; aluminum gallium arsenide (Al0.45Gaa55As) emitter layer A; gallium arsenide (GaAs) ohmic contact layer. The emitter layer of this device includes η plasticized indium gallium, η-type gallium sulfide, and η-type indium gallium; the base layer is a very thin ρ + -type gallium arsenide. The structure of the emitter layer is η aluminum arsenide Gallium (AlGaAs) / nGaAs / n · InGaAs heterostructure, thin copper gallium arsenide (InGaAs) quantum wells at η-GaAs emitter and extremely thin p + E is formed in a gallium (GaAs) base layer. The thickness of each layer is as follows, the gallium arsenide (GaAs) buffer layer (14) is 2,000 A thick, the concentration n + = 3xl018cm-3; the gallium tritide (GaAs) set The electrode layer (16) is 5,000 15 A thick, with a concentration of n = 5xl016cm · 3; the gallium arsenide (GaAs) base layer (18) is 100 A thick, with a concentration of p + =-lxl019cm_3; and an indium gallium arsenide (InuGa ^ As) emitter Layer C (20) 100A thick

Page 9 4 4 1 12 3 _Case No. 891Q 2572__ Year. _ Month 佟 fp_ V. Description of the invention (6) Degree η · = 5xl016cm_3; Gallium arsenide (GaAs) emitter layer B (22) 500 thick A, concentration 11 = ^ 101½ ^ 3; Al (Ga ^ As) emitter layer (24) thickness 1,000 A, concentration n = 5xl017cnT3; GaAs ohmic contact layer (26) thickness 3000 A, concentration n + = 3xl018cnr3. A method for preparing the functional resonance penetrating heterostructure bipolar transistor of the present invention includes a molecular beam worm crystal method (MBE) or an organic metal vapor deposition method (MOCVD). 10 The Second Secret of the Book-Series H, the common emitter current-voltage output characteristic curve of the bipolar transistor of the work surface resonance material structure; when the base current is greater than l_2mA, the transistor exhibits a significant N-type negative differential Resistance phenomenon. The typical current gain is ⑽ and ⑵ before and after the negative differential resistance occurs, and the standby emitter compensation voltage is only 100mV. Under a smaller base-emitter bias, the structure operates like a general transistor is, but the composite current in the base layer is extremely thin and the neutral base region will be reduced, so a high current gain can be obtained, and its approximate energy band is shown in the figure Mikasa shown. Add a η Hua to the emitter layer

Page 10 441123 r—case number 89102572 f month κ V. Description of the invention ⑺ '------ type) Deified gallium' can reduce the spikes between the emitter and the base, which can reduce the set_emitter Compensation voltage and unnecessary power consumption. Under a larger base-emitter bias condition, the thickness of the n-type amorphized gallium emitter empty layer gradually decreases' and a neutral n-type atheized gallium (GaAs) emitter region will appear. At this time, the energy band of the emitter will be effectively promoted, and a mechanism of resonance penetration will be formed, and the electron resonance penetration will pass from the vacant II Shishenhua (GaAs) barrier (emitter region) to the gallium. ^ GaAs) quantum well, ultra-thin P + atheized gallium (GaAs) base ', its approximate energy band is shown in Figure 3 (b). ίο Figure 4 is a graph of the relationship between the penetration coefficient of the neutral η · GaAs emitter layer and the n_InGaAs conductive band's transmission coefficient versus the energy of the InGaAs quantum well. It can be seen from the figure that two subbands (30 and 120mV) appear in the indium gallium arsenide quantum well. Due to the less obvious 120mV secondary energy band and the relationship between thermal effects at room temperature, the obvious N-type negative differential resistance (negative-15 differential resistance) was observed only once in the experiment. The base region of the device of the present invention uses a very thin layer of p-invited material, so when it is operated at room temperature, the resonance penetration phenomenon (resonant-

441 彳 2 3 Case No. 89102572-Year Month Article fp_ 5. Description of the invention (8) Tunneling effect (RT). The resonance penetration phenomenon has very fast negative-differential resistance (less than O.lps), so the excellent high-speed characteristics have excellent development potential in the related circuits of microwaves and micro-microwaves. . The electrons resonate from the empty gallium arsenide emitter layer (triangular barrier) through the extremely thin base layer to the collector layer of the indium-grafted quantum well, and the collector current shows a high peak-to-valley value (PVCR). 5.3 'As shown in Figures 2 and 3 (b). Therefore, the device of the present invention has excellent transistor and negative differential resistance characteristics, which can increase the application range of the device. 10 The novel functional resonance penetrating heterostructure bipolar transistor of the present invention can achieve the transistor characteristics of high current gain and low compensation voltage, and due to the mechanism of the resonance penetrating of the element, through appropriate bias, it can cause N-type negative differential resistance. In addition, because its high-frequency performance is similar to that of a heterojunction bipolar transistor, the noise of the component is low and the operating frequency can reach very high, so it is very significant in microwave applications, such as low-noise amplifiers. On the other hand, using the characteristics of N-type negative differential resistance

441123 Case No. 89102572 Amendment

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Schematic diagram Figure 1 is a new type of functional resonance penetrating heterostructure bipolar electricity: crystal structure diagram of the present invention. FIG. 2 is a graph showing a common-emitter current-voltage output characteristic curve of a novel functional resonance penetrating heterostructure bipolar electric crystal of the present invention. Figure 3 is a band diagram of a novel functional resonant penetrating heterostructure bipolar transistor of the present invention with smaller base-emitter bias and larger base-emitter bias. (A) High current Gain approximate energy band (b) The thickness of the n-type gallium arsenide empty layer decreases gradually

n ^ GaAs Eg-1.42eV N-AlGaAs Eg = 1.96eV

π-GaAs Ε ^ 1.42 © ν π-AlGaAs Eg = 1.13eV

p + -GaAs Eg-1.42eV n'-GaAs Eg-1.42eV Figure 4 is a graph of the relationship between the penetration coefficient and the energy of a toGaAs quantum well in a novel functional resonant penetrating heterostructure bipolar transistor of the present invention.

Page 14 441 12 3 _Case No. 89102572 __ Brief Description of Drawings Description of Drawings 10... A new type of functional resonance penetrating heterostructure bipolar transistor of the present invention. 12... A substrate made of gallium arsenide (GaAs) material. 5 14 ... a buffer layer made of gallium halide (GaAs) material. 16 .. A collector layer made of GaAs material. 18 .. ... a base layer made of gallium arsenide (GaAs) material. 20 .. ... an emitter layer C formed from an indium-gallium (In ^ Gao sAs) material. 22 .. .. · Emitters made of gallium arsenide (GaAs) materials. ίο 24 ..... an emitter layer made of aluminum gallium arsenide material. 26-An ohmic contact layer made of gallium arsenide material. E. Emitter layer B. Base layer C. Collector layer

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Claims (1)

441123 __ Case No. 89102572_ Years and months of repairing the bird_ VI. Application for patent scope 1. A type of resonance penetrating heterostructure bipolar transistor 'system includes: a substrate, a buffer layer, a collector layer, a base layer , A substrate, an emitter layer C, an emitter layer B, an emitter layer A, and an ohmic contact layer. Among them, a substrate is formed of gallium arsenide (GaAs) material; 5 a buffer layer is formed of gallium arsenide (GaAs) material; a collector layer is formed of gallium arsenide (GaAs) material; a base The emitter layer is formed of gallium arsenide (GaAs) material; an emitter layer C is formed of indium gallium arsenide (Jn ^ Ga ^ As) material; the emitter layer B is made of gallium arsenide (GaAs) The material is formed. 10 An emitter layer A is formed of aluminum gallium arsenide (Al0.45Ga0.55As) material; an ohmic contact layer is formed of gallium carbide (GaAs) material. 2. If the resonant penetrating heterostructure bipolar transistor of item 丨 of the patent application scope, the substrate is formed of GaAs. 3. If the resonance penetrating heterostructure bipolar transistor of item 1 of the application scope is applied, the buffer layer is formed of a type of gallium arsenide (GaAs) material. 4 · If you apply for a patent! The resonance of the term penetrating the heterobrain bipolar transistor, 4 41 12 3 ___Case No. 89102572__Year Month Date Amendment ____ VI. Scope of Patent Application The collector layer is formed of n-type gallium Kunas (GaAs) material. 5_ The resonance penetrating heterostructure bipolar transistor according to item 1 of the scope of the patent application. The base layer is formed of an extremely thin p + -type gallium arsenide (GaAs) material. 6. The resonant penetrating heterostructure bipolar transistor according to item 1 of the scope of the patent application. The emitter layer C is formed of η · type indium gallium arsenide (in ^ Ga ^ As) material. 7 &apos; As the resonant penetrating heterostructure bipolar transistor in the first scope of the patent application, the emitter layer B is formed of an n-type gallium arsenide (GaAs) material. 8. As for the scope of patent application! The resonance of the term penetrates a bipolar transistor of a heterostructure, and the emitter layer is formed of a ri-type aluminum gallium arsenide (AI45〇a〇55As) material. m 1 10. The ohmic contact layer is formed of an n + -type arsenide (GaAs) material as the resonant penetrating heterostructure bipolar transistor of item 1 of the scope of patent application. 15