GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Graded base type-II InP/GaAsSb DHBT with f/sub T/=475 GHz

The first demonstration of a type-II InP/GaAsSb double heterojunction bipolar transistor (DHBT) with a compositionally graded InGaAsSb to GaAsSb base layer is presented. A device with a 0.4/spl times/6 /spl mu/m/sup 2/ emitter dimensions achieves peak f/sub T/ of 475 GHz (f/sub MAX/=265 GHz) with current density at peak f/sub T/ exceeding 12 mA//spl mu/m/sup 2/. The structure consists of a 25-nm InGaAsSb/GaAsSb graded base layer and 65-nm InP collector grown by MBE with breakdown voltage /spl sim/4 V which demonstrates the vertical scaling versus breakdown advantage over type-I DHBTs.     

InP/GaAsSb/InP double HBTs: a new alternative for InP-based DHBTs

We report on the physical operation and performance of MOCVD-grown abrupt heterojunction InP/GaAs_0.51Sb_0.49/InP double heterojunction bipolar transistors (DHBTs). In particular, the effect of the InP collector thickness on the breakdown voltage and on the current gain cutoff frequency is assessed and a f_T of 106 GHz is reported for a DHBT with a 400 Å base and a 2000 Å InP collector with a BV_CEO of 8 V. We show that InP/GaAsSb/InP DHBTs are characterized by a weak variation of f_T as a function of temperature. Finally, we also demonstrate that high maximum oscillation frequencies f_MAX>f_T can be achieved in scaled high-speed InP/GaAsSb/InP DHBTs, and provide estimates of the maximum cutoff frequencies achievable for this emergent but promising material system. Recent results on improved structures validate our performance predictions with cutoff frequencies well beyond 200 GHz     

High-Current-Gain InP/GaInP/GaAsSb/InP DHBTs With fT = 436 GHz

Combining a pseudomorphically strained (Ga,In)P emitter with a GaAs_0.6Sb_0.4 base effectively eliminates the emitter heterojunction type-II conduction band offset in InP/GaAsSb double heterojunction bipolar transistors (DHBTs). A peak f_T of 436 GHz at J_C = 10 mA/mum², with BV_CEO = 3.8 V, is achieved with 0.6 times 5 mum² InP/GalnP/GaAsSb DHBTs with a 75-nm InP collector. Compared to a binary InP emitter, the (Ga,In)P emitter doubles the DC current gain from 166 to 338 for otherwise identical devices. These are the highest DC current gain and cutoff frequencies to date in uniform base GaAsSb DHBTs. The gain improvement reported here will greatly facilitate device design tradeoffs that are encountered while scaling InP/GaAsSb DHBTs toward higher frequencies by allowing higher base doping levels and smaller emitter geometries.     

Low-power InP/GaAsSb/InP DHBT cascode transimpedance amplifier with GBP/P/sub dc/ of 7.2 GHz/mW

A low-power high gain-bandwidth monolithic cascode transimpedance amplifier using novel InP/GaAsSb/InP DHBT technology was investigated. The amplifier exhibited state-of-the-art performance of 17.3 dB gain, 12 GHz bandwidth, 55 dB/spl Omega/ transimpedance, and a corresponding gain-bandwidth of 6.7 THz/spl Omega/ while consuming only 12.2 mW DC power. It also achieved good gain-bandwidth-product per DC power figure-of-merit (GBP/P/sub dc/) of 7.2 GHz/mW     

15-nm base type-II InP/GaAsSb/InP DHBTs with F/sub T/=384 GHz and a 6-V BV/sub CEO/

Type-II InP/GaAsSb/InP double heterojunction bipolar transistors (DHBTs) with a 15-nm base were fabricated by contact lithography: 0.73/spl times/11 /spl mu/m/sup 2/ emitter devices feature f/sub T/=384GHz (f/sub MAX/=262GHz) and BV/sub CEO/=6V. This is the highest f/sub T/ ever reported for InP/GaAsSb DHBTs, and an "all-technology" record f/sub T//spl times/BV/sub CEO/ product of 2304 GHz/spl middot/V. This result is credited to the favorable scaling of InP/GaAsSb/InP DHBT breakdown voltages (BV/sub CEO/) in thin collector structures.     

Temperature dependence of DC characteristics of NpN InP/GaAsSb/InP double heterojunction bipolar transistors: an analytical study

An analytic study of DC characteristics based on the drift-diffusion approach has been performed for the InP/GaAsSb DHBTs. The current transport of InP/GaAsSb/InP DHBTs has been investigated focusing the device temperature dependence. Our simulation results show that, at room temperature, the DC characteristics of the InP/GaAsSb/InP DHBTs similar to the conventional InP-based HBT using InGaAs as the base layer although a type-II energy band alignment is presented in the InP/GaAsSb HBT. However, due to different mechanisms for the electron injection from the emitter induced by the different conduction band alignments, the InP/GaAsSb HBTs may present a different temperature dependent behavior in term of device current gain as compared to the conventional InP/InGaAs HBTs. Higher current gain could be achieved by the InP/GaAsSb HBTs at elevated temperature.     

基于InP衬底的GaAsSb/InP异质结晶体管

采用金属有机化学气相沉积生长了InP/GaAs0.5Sb0.5/InP 双异质结晶体三极管(DHBT)材料,研究了材料质量对器件性能的影响.制备的器件不但具有非常好的直流特性,而且还表现出良好的微波特性,其结果与能带理论的预言一致,DHBT集电结和发射结的电流理想因子分别为1.00和1.06,击穿电压高达15V,电流放大增益截止频率超过100GHz.     

Low turn-on voltage InGaP/GaAsSb/GaAs double HBTs grown by MOCVD

A novel InGaP/GaAs_0.92Sb_0.08/GaAs double heterojunction bipolar transistor (DHBT) with low turn-on voltage has been fabricated. The turn-on voltage of the DHBT is typically 150 mV lower than that of the conventional InGaP/GaAs HBT, indicating that GaAsSb is a suitable base material for reducing the turn-on voltage of GaAs HBTs. A current gain of 50 has been obtained for the InGaP/GaAs_0.92Sb_0.08/GaAs DHBT. The results show that InGaP/GaAsSb/GaAs DHBTs have a great potential for reducing operating voltage and power dissipation     

基于InP衬底的GaAsSb/InP异质结晶体管

采用金属有机化学气相沉积生长了InP/GaAs0.5Sb0.5/InP 双异质结晶体三极管(DHBT)材料,研究了材料质量对器件性能的影响.制备的器件不但具有非常好的直流特性,而且还表现出良好的微波特性,其结果与能带理论的预言一致,DHBT集电结和发射结的电流理想因子分别为1.00和1.06,击穿电压高达15V,电流放大增益截止频率超过100GHz.     

GaAsSb for heterojunction bipolar transistors

The advantages of using GaAsSb in heterojunction bipolar transistors (HBT) are discussed with emphasis on two recent experimental results in the AlGaAs/GaAsSb material system. The performances of a prototype n-p-n AlGaAs/GaAsSb/GaAs double HBT (DHBT) that exhibits stable current gain with maximum collector current density of 5×10 ⁴ A/cm², and a p-n-p AlGaAs/GaAs HBT with a superlattice GaAsSb emitter ohmic contact which has a specific contact resistivity of 5±1×10^-7 Ω-cm² across the sample, are examined     

Monolithically integrated long wavelength photoreceiver OEIC based on InP/InGaAs HBT technology

The epitaxial structure and growth, circuit design, fabrication process and characterization are described for the photoreceiver opto-electronic integrated circuit (OEIC) based on the InP/lnGaAs HBT/PIN photodetector integration scheme. A 1.55 μm wavelength monolithically integrated photoreceiver OEIC is demonstrated with self-aligned InP/lnGaAs heterojunction bipolar transistor (HBT) process. The InP/lnGaAs HBT with a 2 μm × 8 μm emitter showed a DC gain of 40, a DC gain cutoff frequency of 45 GHz and a maximum frequency of oscillation of 54 GHz. The integrated InGaAs photodetector exhibited a responsivity of 0.45 AAV at λ = 1.55 μm, a dark current less than 10 nA at a bias of -5 V and a -3 dB bandwidth of 10.6 GHz. Clear and opening eye diagrams were obtained for an NRZ 223-l pseudorandom code at both 2.5 and 3.0 Gbit/s. The sensitivity for a bit error ratio of 10-9 at 2.5 Gbit/s is less than -15.2 dBm.     

InP/GaAsSb/InP双异质结双极晶体管技术发展现状(Ⅰ)

InP/GaAsSb/InP双异质结双极晶体管(DHBT)以其独特的交错Ⅱ型能带结构,在频率特性、击穿特性和热特性等方面较传统的InP/InGaAsSHBT与InP/InGaAs/InPDHBT等显示出极大的优越性。对InP/GaAsSb/InPⅡ型DHBT技术的提出、外延层结构设计与生长、器件结构设计、器件制造工艺与优化以及国内外发展情况研究水平、发展趋势和商业化情况进行了系统的回顾和展望。指出结合垂直方向材料结构优化缩小器件尺寸和采用微空气桥隔离基极电极结构是InP/GaAsSb/InPDHBT向THz截止频率发展的最重要的技术路线。     

300 GHz InP/GaAsSb/InP double HBTs with high current capability andBVCEO>6 V

We report MOCVD-grown NpN InP/GaAsSb/InP abrupt double heterojunction bipolar transistors (DHBTs) with simultaneous values of f _T and f_MAX as high as 300 GHz for J_C=410 kA/cm² at V_CE=1.8 V. The devices maintain outstanding dynamic performances over a wide range of biases including the saturation mode. In this material system the p+ GaAsSb base conduction band edge lies 0.10-0.15 eV above the InP collector conduction band, thus favoring the use of nongraded base-collector designs without the current blocking effect found in conventional InP/GaInAs-based DHBTs. The 2000 Å InP collector provides good breakdown voltages of BV_CEO=6 V and a small collector signal delay of ~0.23 ps. Thinner 1500 Å collectors allow operation at still higher currents with f_T>200 GHz at J_C=650 kA/cm²     

10-GHz power performance of a type II InP/GaAsSb DHBT

Type-II InP/GaAsSb double heterojunction bipolar transistors (DHBTs) were fabricated and microwave power performance was measured. For an InP collector thickness of 150 nm, the DHBTs show a current gain of 24, low offset voltages, and a BV/sub CEO/>6V. The 1.2/spl times/16 /spl mu/m/sup 2/ devices show f/sub T/=205GHz and f/sub MAX/=106GHz at J/sub C/=304 kA/cm/sup 2/. These devices delivered 12.6 dBm to the load at P/sub AVS/=3.3 dBm operating at 10 GHz, yielding a power-added efficiency of 41% and G/sub T/=9.3 dB.     

High fmax InP double heterojunction bipolar transistorswith chirped InGaAs/InP superlattice base-collector junction grown byCBE

We report the performance of InP Double Heterojunction Bipolar Transistors (DHBT's) with a chirped InGaAs/InP superlattice B-C junction grown by CBE. The B-C junction of the DHBT was graded with a 10-period InGaAs/InP chirped superlattice (CSL) between the InGaAs base and the lightly doped InP collector. A highly doped thin layer was also included at the end of the CSL to offset the quasi-electric field arising from the grade and suppress further the carrier blocking effect across the B-C heterojunction. The InP/InGaAs CSL DHBT demonstrated a high BV_CEO of 18.3 V with a typical current gain of 55 with minimal carrier blocking up to high current densities. Maximum cutoff frequencies of f_max=146 GHz and f_r=71 GHz were obtained from the fabricated 2×10 μm²-emitter DHBT     

MBE生长的InP DHBT的性能

报道了一种自对准InP/InGaAs 双异质结双极晶体管的器件性能.成功制作了U型发射极尺寸为2μm×12μm的器件,其峰值共射直流增益超过300,残余电压约为0.16V,膝点电压仅为0.6V,而击穿电压约为6V.器件的截至频率达到80GHz,最大震荡频率为40GHz.这些特性使此类器件更适合于低压、低功耗及高频方面的应用.     

A 183 GHz f/sub T/ and 165 GHz f/sub max/ regrown-emitter DHBT with abrupt InP emitter

Small-area regrown emitter-base junction InP/In-GaAs/InP double heterojunction bipolar transistors (DHBT) using an abrupt InP emitter are presented for the first time. In a device with emitter-base junction area of 0.7 /spl times/ 8 /spl mu/m/sup 2/, a maximum 183 GHz f/sub T/ and 165 GHz f/sub max/ are exhibited. To our knowledge, this is the highest reported bandwidth for a III-V bipolar transistor utilizing emitter regrowth. The emitter current density is 6/spl times/10/sup 5/ A/cm/sup 2/ at V/sub CE,sat/ = 1.5 V. The small-signal current gain h/sub 21/ = 17, while collector breakdown voltage is near 6 V for the 1500-/spl Aring/-thick collector. The emitter structure, created by nonselective molecular beam epitaxy regrowth, combines a small-area emitter-base junction and a larger-area extrinsic emitter contact, and is similar in structure to that of a SiGe HBT. The higher f/sub T/ and f/sub max/ compared to previously reported devices are achieved by simplified regrowth using an InP emitter and by improvements to the regrowth surface preparation process.     

High gain AllnAs/GaAsSb/AllnAs NpN HBTs on InP

We report the first growth and characterization of high gain double heterojunction NpN HBTs on InP with a lattice-matched GaAs₅Sb₅ base layer. This AllnAs/GaAsSb heterojunction has almost no discontinuity in the conduction band edge, eliminating the need to grade the emitter-to-base heterojunction to achieve optimal carrier injection. The layers were grown in a solid source MBE system, using tetramer As₄ and Sb₄ sources. Be is an efficient acceptor in the GaAsSb, but the mobility is about half that measured inp type GaAs on GaAs substrates. The HBTs fabricated were large area mesa isolated transistors, with a beta of 80 at a current density of 2 kA/cm², and the gain remained high at lower current densities. The turnon voltage,V _be, is only 0.45 V at a current density of 2 A/cm².     

Emitter-Size Effects and Ultimate Scalability of InP:GaInP/GaAsSb/InP DHBTs

Emitter-size effects (ESEs) are experimentally investigated in GaAsSb-based double heterojunction bipolar transistors (DHBTs) with a new InP:GaInP composite emitter. This letter reveals that both the extrinsic base surface recombination and the intrinsic space charge recombination directly under the emitter are effectively suppressed over a wide range of collector current densities by eliminating the type-II conduction band at the emitter-base heterojunction. The reduction of ESEs enables aggressive scaling and suggests that the GaInP/GaAsSb heterojunction could become a key enabling element for sub-100-nm terahertz bandwidth InP/GaAsSb DHBTs.