InGaAs/InP微波双极型晶体管的研制

本文叙述双收集区NpnN型InGaAs/InP异质结双极型晶体管的实验结果.给出器件的击穿特性、开关特性.高频特性和温度特性.理论分析和实验结果表明,n型InGaAs第一收集区的厚度对晶体管的击穿特性和开关特性有重要影响.器件的击穿电压BV_(CE0)=20伏,贮存时间t_s=0.5ns(Ic=50mA,I_(B1)=10mA,回抽电流I_(B2)=0),f_T=1.2GHz(V_(CE)=6V,Ic=15mA).在77～433K范围内h_(fe)变化很小,在4K下h_(fe)≌1,并表现出强烈的俄立(Early)效应.     

ft =203GHz的超高速InP/InGaAs双异质结晶体管

为了适应数字及模拟电路带宽的不断增加,我们在传统的台面结构基础上利用BCB钝化平坦化工艺技术,设计并研制了InP/InGaAs/InP双异质结双极型晶体管。我们研制的晶体管ft达到203GHz,是目前国内InP基DHBT的最高水平,发射极尺寸为1.0μm×20μm,电流增益β为166,击穿电压为4.34V,我们的器件采用了40nm高掺杂InGaAs基区,以及203nm含有InGaAsP复合式结构的集电区。该器件非常适合高速中功耗方面的应用。     

硅晶体管禁带宽度的测定

禁带宽度是硅晶体管的一个重要物理参数,本文根据晶体管pn发射结反向饱和电流和正向偏置电压的温度特性,提出了利用线性外推法确定硅晶体管各区域在0K时的禁带宽度的新方法。由于发射区重掺杂,还考虑了载流子的简并情况。本文主要取决于直流参量的温度特性,所得结果比较精确。 结果如下:对于发射区掺杂浓度N_E=1×10~(20)cm~_3,其禁带宽度E_(gE0)=1.056eV;对于集电区掺杂浓度N_C=5×10~(15)cm~(-3),其禁带宽度E_(gC0)=1.198eV。     

带有阶梯缓变集电区的InP/InGaAs/InP DHBT材料研究

设计并生长了一种新的InP/InGaAs/InP DHBT结构材料,采用在基区和集电区之间插入两层不同禁带宽度的InGaAsP四元系材料的阶梯缓变集电结结构,以解决InP/InGaAs/InP DHBT集电结导带尖峰的电子阻挡效应问题。采用气态源分子束外延(GSMBE)技术,通过优化生长条件,获得了高质量的InP、InGaAs以及与InP晶格相匹配的不同禁带宽度的InGaAsP外延材料。在此基础上,成功地生长出带有阶梯缓变集电区结构的InP基DHBT结构材料。     

带有复合掺杂层集电区的InP/InGaAs/InP DHBT直流特性分析

设计了一种新结构InP/InGaAs/InP双异质结双极晶体管(DHBT),在集电区与基区之间插入n+-InP层,以降低集电结的导带势垒尖峰,克服电流阻挡效应.采用基于热场发射和连续性方程的发射透射模型,计算了n+-InP插入层掺杂浓度和厚度对InP/InGaAs/InP DHBT集电结导带有效势垒高度和I-V特性的影响.结果表明,当n+-InP插入层掺杂浓度为3×1019cm-3、厚度为3nm时,可以获得较好的器件特性.采用气态源分子束外延(GSMBE)技术成功地生长出InP/InGaAs/InP DHBT结构材料.器件研制结果表明,所设计的DHBT材料结构能有效降低集电结的导带势垒尖峰,显著改善器件的输出特性.     

InGaAsP/InP准平面异质结双极晶体管及其与光器件的集成

本文采用计算机辅助分析等方法,讨论了InGaAs/InP异质结双极晶体管(HBT)结构参数与其性能的关系.在此基础上,提出了一种准平面、双集电区HBT,及其相应的制作工艺.初步测试了器件的性能,就其与材料质量的关系作了讨论.文章还提出和制作了一种采用这种HBT为电子器件的光电子集成电路(OEIC).     

带有复合掺杂层集电区的InP/InGaAs/InP DHBT直流特性分析

设计了一种新结构InP/InGaAs/InP双异质结双极晶体管(DHBT),在集电区与基区之间插入n -InP层,以降低集电结的导带势垒尖峰,克服电流阻挡效应.采用基于热场发射和连续性方程的发射透射模型,计算了n -InP插入层掺杂浓度和厚度对InP/InGaAs/InP DHBT集电结导带有效势垒高度和I-V特性的影响.结果表明,当n -InP插入层掺杂浓度为3×1019cm-3、厚度为3nm时,可以获得较好的器件特性.采用气态源分子束外延(GSMBE)技术成功地生长出InP/InGaAs/InP DHBT结构材料.器件研制结果表明,所设计的DHBT材料结构能有效降低集电结的导带势垒尖峰,显著改善器件的输出特性.     

透明CdO膜发射区InGaAs光电晶体管

研制出一种新型的InGaAs光电晶体管。其发射区采用导电率高(σ=5×10~3Ω~(-1)cm~(-1))禁带宽(E_g(Γ)=2.5eV)的氧化镉(CdO)透明膜,形成宽发射区。测试结果表明,该管具有较宽的波长响应(λ=0.5～1.6μm),共发射极电流增益h_(fe)为10(V_(CE)=3V,I_C=1mA)。并对发射结的伏安恃性、h_(fe)-I_C及暗电流等进行了讨论。     

用氧化镉(CdO)做宽发射区的磷化铟平面型扩散晶体管

本文提出了一种新型的异质结双极型晶体管.该管的收集区和基区由磷化铟材料做成.和硅平面晶体管类似,管子的基区采用一般的氧化层(Al_2O_3)掩蔽扩散工艺(在这里是锌扩散).而管子的发射区则采用溅射氧化镉簿层的方法形成,因而管子的结构是平面型的.氧化镉是一种宽禁带(Eg=2.3eV)的N型半导体.氧化镉和磷化铟组成了晶体管的宽发射极.本文介绍了制管工艺.给出并分析了晶体管的伏一安特性.初步结果是:晶体管共发射极电流增益h_f_a=10(I_C=50mA,V_(cr)=15V).发射极一收集极间的击穿电压BV_(CED)=30V.这种晶体管及其工艺为InGaASP/InP器件及其光电集成制作提供了一条可能的新途径.     

硅异质结晶体管的试制

本文较详细地分析了Si/α-Si异质结晶体管(HBT)的微波性能和工艺优点,简述了工艺过程,初步实验结果证实:Si/α-Si HBT具有较好的小电流特性,晶体管的h_(fe)=12(V_(CE=10V,I_C=1mA),BV_(CEO)=20V。     

Be diffusion in InGaAs/InP heterojunction bipolar transistors

Classic signatures of Be diffusion were observed in InAlAs/InGaAs HBT's after elevated temperature bias stress, i.e., a positive shift in the Gummel plot, higher collector ideality, and higher offset voltage. An activation energy of 1.57 eV was calculated. Lifetimes of 3.3×106 h and 37000 h were extrapolated for low and high power operation, respectively. In contrast, an InP/InGaAs HBT with a C doped base showed no signatures of C diffusion. The results show that Be diffusion is manageable at lower power. They also support the idea that C is more stable than Be in this material system     

Multiterminal light-emitting logic device electricallyreprogrammable between OR and NAND functions

A monolithic multiterminal logic device that functions both optically and electrically as an ORNAND gate, is demonstrated for the first time. The device, based on the real-space transfer of hot electrons into a complementary collector layer, has been implemented in an InGaAs/InAlAs/InGaAs heterostructure grown by molecular beam epitaxy. Excellent performance is obtained at room temperature. The collector current and the optical output power both exhibit the OR and the NAND functions of any two of the three input terminals, these functions being interchangeable by the voltage on the third terminal     

Stress current behavior of InAlAs/InGaAs and AlGaAs/GaAs HBT's withpolyimide passivation

InAlAs/InGaAs and AlGaAs/GaAs HBTs, with heavily Be-doped base layers, have been fabricated and their reliability under excessive forward current tested. To understand the HBT material difference, a common process based on a polyimide planarization method is applied to the fabrication. While short-term degradation induced by stress current is observed for AlGaAs/GaAs HBTs, InAlAs/InGaAs HBTs are stable up to a current density of 1.5×10⁵ A/cm², indicating the absence of substantial Be diffusion. An analysis of base current has shown a striking contrast between the HBTs in terms of the stressing effect on the surface recombination along emitter junction periphery     

Light-emitting transistor based on real-space transfer: electricaland optical properties

The charge injection transistor is implemented in InGaAs/InAlAs/InGaAs heterostructure material, grown by molecular beam epitaxy. A complementary collector of p-type conductivity is used for the first time. The real-space transfer of hot electrons leads to a luminescence signal proportional to the injection current. The radiative efficiency is significantly enhanced by a double-heterostructure design of the collector active region, which confines the injected minority carriers. The internal quantum efficiency of the light-emitting transistor is comparable to that of light-emitting diodes. Due to peculiar symmetry of real-space transfer, the optical output signal follows an exclusive-OR function of input voltages. Functional logic operation of the device is demonstrated at room temperature     

Design, modeling, and characterization of monolithically integratedInP-based (1.55 μm) high-speed (24 Gb/s) p-i-n/HBT front-endphotoreceivers

High-speed, long-wavelength InAlAs/InGaAs OEIC photoreceivers based on a p-i-n/HBT shared layer integration scheme have been designed, fabricated and characterized. The p-i-n photodiodes, formed with the 6000 Å-thick InGaAs precollector layer of the HBT as the absorbing layer, exhibited a responsivity of ~0.4 A/W and a -3 dB optical bandwidth larger than 20 GHz at λ=1.55 μm. The fabricated three-stage transimpedance amplifier with a feedback resistor of 550 Ω demonstrated a transimpedance gain of 46 dBΩ and a -3 dB bandwidth of 20 GHz. The monolithically integrated photoreceiver with a 83 μm p-i-n photodiode consumed a small dc power of 35 mW and demonstrated a measured -3 dB optical bandwidth of 19.5 GHz, which is the highest reported to date for an InAlAs/InGaAs integrated front-end photoreceiver. The OEIC photoreceiver also has a measured input optical dynamic range of 20 dB. The performance of individual devices and integrated circuits was also investigated through detailed CAD-based analysis and characterization. Transient simulations, based on a HSPICE circuit model and previous measurements of eye diagrams for a NRZ 2³¹-1 pseudorandom binary sequence (PRBS), show that the OEIC photoreceiver is capable of operation up to 24 Gb/s     

High-speed InAlAs/InGaAs heterojunction bipolar transistors

InAlAs/InGaAs heterojunction bipolar transistors fabricated from wafers grown by molecular beam epitaxy are discussed. A cutoff frequency of 32 GHz for a collector current of 20 mA is achieved in the emitter area of devices 6×10 μm². The use of heavily doped and nondoped InGaAs layers as the emitter cap and collector, respectively, results in a reduction of the emitter and collector charging times; this, in turn, leads to improved microwave performance     

Improvement of Impact Ionization Effect and Subthreshold Current in InAlAs/InGaAs Metal–Oxide–Semiconductor Metamorphic HEMT With a Liquid-Phase Oxidized InAlAs as Gate Insulator

The oxidation of InAlAs and its application to InAlAs/InGaAs metal-oxide-semiconductor metamorphic high-electron mobility transistors (MOS-MHEMTs) are demonstrated in this study. After the highly selective gate recessing of InGaAs/InAlAs using citric buffer etchant, the gate dielectric is obtained directly by oxidizing the InAlAs layer in a liquid-phase solution at near room temperature. As compared to its counterpart MHEMT, the fabricated InAlAs/InGaAs MOS-MHEMT exhibits a larger tolerance to gate bias, higher breakdown voltage, lower subthreshold current, improved gate leakage current with the effectively suppressed impact ionization effect, and improved radio-frequency performance. Consequently, the liquid-phase oxidation may also be used to produce gate oxides and as an effective passivation on III-V compound semiconductor devices     

InAlAs/InGaAs HBT X-band double-balanced upconverter

We report on an InAlAs/InGaAs HBT Gilbert cell double-balanced mixer which upconverts a 3 GHz IF signal to an RF frequency of 5-12 GHz. The mixer cell achieves a conversion loss of between 0.8 dB and 2.6 dB from 5 to 12 GHz. The LO-RF and IF-RF isolations are better than 30 dB at an LO drive of +5 dBm across the RF band. A pre-distortion circuit is used to increase the linear input power range of the LO port to above +5 dBm. Discrete amplifiers designed for the IF and RF frequency ports make up the complete upconverter architecture which achieves a conversion gain of 40 dB for an RF output bandwidth of 10 GHz. The upconverter chip set fabricated with InAlAs/InGaAs HBT's demonstrates the widest gain-bandwidth performance of a Gilbert cell based upconverter compared to previous GaAs and InP HBT or Si-bipolar IC's     

双基区条准平面型InAlAs/InGaAs异质结双极型晶体管

本文提出和制作了双基区条准平面InAIAs/InGaAs HBT.准平面和低基区电阻是该设计的主要特点.文中介绍了制管工艺.直流特性的测量表明,器件的共发射极增益h_(fe)为50左右.     

Characterization of current-induced degradation in Be-doped HBTsbased in GaAs and InP

The changes in the device characteristics under high-bias conditions are investigated for InAlAs/InGaAs and AlGaAs/GaAs heterojunction bipolar transistors (HBTs) with heavily Be-doped base lasers, focusing on the base current and 1/f noise characteristics. It is shown that the ideality factor of the surface recombination base current provides information on the Be movement accompanying the degradation. For stress current densities up to 1.5×10⁵ A/cm², the Be movement in the InAlAs/InGaAs HBTs is estimated to be no more than a small fraction of the 5 nm setback layer. The 1/f noise measurement highlight the effect of current stressing on the surface recombination in the HBTs. A characteristic spectral shape is found in the noise spectra for the current-stressed AlGaAs/GaAs HBT, possibly originating from the degradation-induced carrier traps. Although both HBTs have similar electronic properties, these results illustrate the striking difference in their stress current behaviors