台面型InP/InGaAs PIN光伏探测器的p-InP低阻欧姆接触

研究了电子束蒸发淀积的非合金膜系Au/Pt/Ti/p-InP(2×1018cm-3)接触的物理特性,通过450℃、4 min的快速退火,获得了欧姆接触,其比接触电阻为7.3×10-5 Wcm2.接触电极退火后,采用离子溅射法淀积加厚电极Cr/Au.利用俄歇电子能谱(AES)进行深度剖面分析,表明Pt层能够相对有效地阻挡...     

Temperature dependent study of carbon-doped InP/InGaAs HBT's

We report on a temperature dependent study of the dc and the microwave performance of carbon-doped InP/In_0.53Ga_0.47 As heterojunction bipolar transistors (HBT's). The turn on voltage increased 114% and the dc current gain decreased 25% as the temperature was reduced from 300 K to 33 K. Under high-current injection, there was a 29% increase in the current gain cutoff frequency of these devices as the temperature was lowered from 300 K to 77 K. By investigating the operation of HBT's at cryogenic temperatures, increased understanding of the mechanisms of carrier transport in these devices can be obtained, and this may lead to improvements in device performance     

Ideal ohmic contacts to InP

A new method of producing ohmic contacts to semiconducting n-type InP by the use of a slow alloying cycle with a P overpressure has resulted in improved contact fabrication. Gunn devices were produced with these contacts for the anode and cathode and their microwave characteristics were measured.     

Au/Ge/Ni ohmic contacts to n-Type InP

The relationship between the electrical properties and microstructure for annealed Au/Ge/Ni contacts to n-type InP, with an initial doping level of 10¹⁷ cm^-3, have been studied. Metal layers were deposited by electron beam evaporation in the following sequence: 25 nm Ni, 50 nm Ge, and 40 nm Au. Annealing was done in a nitrogen atmosphere at 250-400‡C. The onset of ohmic behavior at 325‡C corresponded to the decomposition of a ternary Ni-In-P phase at the InP surface and the subsequent formation of Ni₂P plus Au₁₀In₃, producing a lower barrier height at the InP interface. This reaction was driven by the inward diffusion of Au and outward diffusion of In. Further annealing, up to 400‡C, resulted in a decrease in contact resistance, which corresponded to the formation of NiP and Au₉ln₄ from Ni₂P and Au₁₀In₃,respectively, with some Ge doping of InP also likely. A minimum contact resistance of 10^-7 Ω-cm² was achieved with a 10 s anneal at 400‡C.     

Microwave low-noise AlGaAs/InGaAs HBT's with p+-regrownbase contacts

This paper reports low-noise AlGaAs/InGaAs heterojunction bipolar transistors (HBT's) with p⁺-regrown base contacts. To reduce the thermal and shot noises, we have reduced R_B by using a p ⁺-regrown base contact and have reduced τ_B by using a compositionally-graded thin base layer. As a result, F_min values of 0.9, 1.1, 1.2, and 1.6 dB were obtained at 2, 6, 12, and 18 GHz, respectively. These low-noise characteristics of our HBT's show high potential for low-noise application     

A high speed burst mode optoelectronic integrated circuitphotoreceiver using InP/InGaAs HBT's

A novel monolithic differential photoreceiver has been realized using InP/InGaAs heterojunction bipolar transistors. This dc-coupled differential OEIC operated successfully with both continuous and burst-mode data streams up to 5 Gb/s with a sensitivity of -18.6 dBm for the continuous mode operation at a bit error rate of 10^-9. There was a 1.5 dB penalty of the sensitivity value in burst-mode operation. This is the first demonstration of an OEIC for burst-mode operation at high speeds     

AuGe/Au ohmic contacts to n-type InP by hot-plate alloying

The authors report on the fabrication and characteristics of AuGe/Au ohmic contacts to ion-implanted n-type InP. The contacts have smooth surface morphology, excellent adhesion and good contact resistance uniformity. For samples with carrier concentrations of 1.7 * 10/sup 17/ and 1.6 * 10/sup 18/ cm/sup -3/, contact resistances of 0.07 and 0.03 Omega mm, respectively, have been obtained. These values are among the lowest contact resistances reported for n-type InP.<>     

InP mixer diodes with etched via ohmic contacts

InP mixer diodes processed with Ag/TiW/Au Schottky diodes have exhibited a noise figure of 6.5?7.0 dB at 94 GHz. InP surface preparation is shown to be critical in diode performance. An indium-stabilised surface has resulted in a barrier height of 0.45 eV.     

Pd/Zn/Pd/Au ohmic contacts to ρ-Type InP

Low resistance ohmic contacts (ρ_c = 7 x 10^-5 Ω-cm ² ) have been fabricated to Zn-doped p-type InP using an annealed Pd/Zn/Pd/Au metallization. Palladium reacts with InP at low temperatures to form a Pd₂InP ternary phase, which is initially amorphous but crystallizes and grows epitaxially on InP. Zinc reacts with some of the overlying Pd to form PdZn (≅250° C), which decomposes at 400-425° C to form PdP₂, freeing up Zn to diffuse into Au as well as InP. The contact resistance reaches a minimum as the decomposition reaction takes place. The resultant ohmic contact is laterally uniform and consists of epitaxial Pd₂InP adjacent to InP, followed by a thin layer of PdP₂ and then the outer Au layer. Further annealing leads to a breakdown of the contact structure,i.e. decomposition of Pd₂InP, and an increase in contact resistance.     

异质结InP/InGaAs探测器欧姆接触温度特性研究

为了研究异质结InP/InGaAs探测器帽层的欧姆接触特性,采用Au/p-InP传输线模型(TLM),对比不同退火温度下的接触特性,在480℃、30 s的退火条件下实现室温比接触电阻为3.84×10~(-4)Ω·cm~2,同时,对欧姆接触的温度特性进行了研究,发现随着温度降低比接触电阻增加,在240~353 K温度范围内界面电流传输主要为热电子-场发射机制(TFE);240 K以下,接触呈现肖特基特性.利用扫描电子显微镜(SEM)和X射线衍射仪(XRD)分别对界面处的扩散程度和化学反应进行了分析,发现经过480℃、30 s退火后样品界面处存在剧烈的互扩散,反应产物Au_(10)In_3有利于改善Au/p-InP的接触性能.     

High-performance submicrometer gatelength GaInAs/InP compositechannel HEMT's with regrown ohmic contacts

This letter reports DC and RF performance of 0.25 μm gatelength GaInAs/InP composite channel HEMT's with nonalloyed, regrown ohmic contacts by MOCVD. Regrown channel contacts are used to achieve low contact resistance (0.35 Ω-mm) to (50 Å) GaInAs/(150 Å) InP composite channel HEMT's. High transconductance (600 mS/mm), high full channel current (650 mA/mm), and high peak cut-off frequencies (F_t=70 GHz, F_max=170 GHz) are observed. Contact transfer resistance of regrown channel contacts is compared to conventional alloyed contacts for varying GaInAs/InP channel composition     

Reduction of base-collector capacitance in InP/InGaAs HBT's using anovel double polyimide planarization process

The parasitic base-collector capacitance (C_BC) in InP/InGaAs heterojunction bipolar transistors (HBTs) has been reduced using a novel double polyimide planarization process which avoids damage of the extrinsic base layer. The extrinsic base metal outside the base-collector mesa is placed on the polyimide by polyimide coating and etch-back to the base layer. We obtained f_T of 81 GHz and f _MAX of 103 GHz with a 2×10 μm emitter. Performance comparison between two devices with the same area of 2×2 μm but with different base-collector mesa area showed 56% reduction of C_BC and 35% increase of f_T and f_MAX     

Influence of cap-layer doping on ohmic contacts for InP based HEMT structures

Ohmic contacts to lattice matched InP based HEMT structures with both doped and undoped GaInAs cap-layers have been investigated. Contact resistances as low as 0.09 Ωmm were achieved using annealed Ni---Ge---Au ohmic contacts. It is reported that the contact resistance is independent of the doping of the thin (50–100 Å) cap-layer. This indicates that it is the bandgap and not the doping of the cap-layer, which determines the contact resistance to the HEMT structure. Furthermore it was shown, that the contact resistance is reduced for lower sheet resistances of the 2DEG.     

Long-term thermal stability of Ti/Al/Mo/Au ohmic contacts on n-GaN

Improved performance of the ohmic contacts on n-GaN has been demonstrated with the use of MoAu as the capping layer on TiAl metallization. Contact resistance as low as 0.13 Θ-mm was achieved in these ohmic contacts when annealed at 850°C for 30 sec. We have studied the long-term thermal stability of these contacts at 500°C, 600°C, 750°C, and 850°C, respectively. The Ti/Al/Mo/Au metallization forms low contact-resistance ohmic contacts on n-GaN that are stable at 500°C and 600°C after 25 h of thermal treatment. The ohmic-contact performance degrades after 10 h of thermal treatment at 750°C, while the contacts exhibit nonlinear current-voltage (I-V) characteristics after 1 h of thermal treatment at 850°C with the formation of oxide on the surface of the contacts accompanied by surface discoloration. The intermetallic reactions taking place in the contacts during the long-term thermal treatments were studied using Auger electron spectroscopy (AES), and the surface morphology was characterized using atomic force microscopy (AFM).     

InP/InGaAs异质结双极晶体管研究

阐述了ＩｎＰ／ＩｎＧａＡｓ异质结双极晶体管的最新发展动态,重点讨论了ＨＢＴ的结构与性能以及ＨＢＴＩＣ的高速性能与可靠性问题     

InP/InGaAs heterojunction phototransistors

We describe the fabrication and device characteristics of experimental back-illuminated InP/InGaAs n-p-n heterojunction phototransistors. These devices exhibit photoresponse in the wavelength range of0.95-1.6 mum. An optical gain of 40 at an input power of 1 nW (an improvement of 1000 in sensitivity over previously reported phototransistors) has been observed. Gains as high as 1000 have been achieved for higher incident power levels.     

High-f/sub max/ AlGaAs/InGaAs and AlGaAs/GaAs HBT's with p/sup +//p regrown base contacts

The present paper describes a new approach to fabricating high performance HBT's with low base resistance. Their base contact resistance is reduced by using MOMBE selective growth in the extrinsic base region-a key process in the fabrication of high-f/sub max/ AlGaAs/InGaAs and AlGaAs/GaAs HBT's. A p/sup +//p regrown base structure, which consists of a 40-nm-thick graded InGaAs strained layer and a heavily C-doped regrown contact layer, is used for the AlGaAs/InGaAs HBT's to reduce both their base transit time and base resistance, while preventing aluminum oxide incorporation at the regrowth interface. An h/sub fe/ of 93, an f/sub T/ of 102 GHz, and an f/sub max/ of 224 GHz are achieved for a 1.6-/spl mu/m/spl times/4.6-/spl mu/m HBT, together with reduced base push-out effects and improved reliability. AlGaAs/GaAs HBT's with an 80-nm-thick uniform base layer that have high f/sub max/ values ranging from 140-216 GHz are also fabricated using the selective growth technique. These results confirm the high potential of the proposed HBT's, especially for microwave and millimeter-wave applications.<>     

高速InP/InGaAs HBT

<正> 最近TI公司报道了一种甚高性能的InP/InGaAs HBT,其f_(max)为180GHz,f_T为100GHz,电流密度为1×10~5A/cm~2。有效延迟时间(f_T/8πf_(max)~2)为0.2ps,这是已报道的共发射极InP/InGaAsHBT中的最小值。 这     

The thermal stability of ohmic contact to n-type InGaAs layer

The thermal stability of ohmic contact to n-type InGaAs layer is investigated. When Ni/Ge/Au is used as the contact metal, the characteristics of the ohmic contact are degraded after thermal treatment. The specific contact resistance of (Ni/Ge/Au)-InGaAs ohmic contact after annealing at 450°C is about 15 times larger than that of as-deposited sample. This is due to the decomposition of InGaAs and the interdiffusion of Ga and Au. A new phase of Au₄ln appears after annealing at 300°C. While in the case of Ti/Pt/Au, Au does not penetrate into the InGaAs layer as revealed by secondary ion mass spectroscopy. The specific contact resistance of (Ti/Pt/Au)-InGaAs ohmic contact after annealing at 450°C is eight times larger than that of as-deposited sample. Therefore, the thermal stability of (Ti/Pt/Au)-InGaAs ohmic contact is better than that of (Ni/Ge/Au)InGaAs ohmic contact.