CMOS图像传感器抗电离辐射加固技术研究

太空环境中的电离辐射会导致CMOS图像传感器性能退化,甚至造成永久性损毁。文章对CMOS图像传感器抗电离辐射加固技术进行了研究,从版图设计、电路设计等方面提出相应的抗辐射策略,并进行了总剂量和单粒子试验。试验结果表明,采用抗辐射加固技术设计制作的CMOS图像传感器具备抗总剂量和单粒子辐射能力,当总剂量达到100krad(Si)、单粒子辐射总注量达到1×10⁷p/cm²时,器件的关键指标变化符合预期要求。     

红外探测器辐照机理分析及辐照试验验证

红外探测器处于太空或辐射环境会受到各种辐射粒子作用,其性能会发生衰减。本文主要分析了各种辐射效应对HgCdTe红外探测器性能影响机理。针对红外探测器复合钝化加固方法,ROIC环源环栅加固方法进行试验验证。辐照试验显示,加固后的红外探测器互联抗辐照读出电路,其抗总剂量、抗剂量率及抗中子辐射位移达到了比较好抗辐照效果。     

P沟道VDMOS器件抗辐射加固技术研究

针对功率器件的抗辐射加固技术,从入射粒子对半导体材料的辐射损伤机理出发,设计了一种-150 V抗辐射P沟道VDMOS器件。该器件采取的抗辐射加固措施有:在颈区的上方形成局部厚场氧化层结构;在N体区进行高剂量离子注入掺杂;在850 ℃低温条件下生长栅氧化层。通过仿真分析和试验进行了验证,该器件在最劣漏偏置条件下抗总剂量达到3 kGy,抗单粒子烧毁和单粒子栅穿的LET值为99.1 MeV·cm²/mg。该器件适用于星用抗辐射DC-DC电源系统。     

抗辐射数字电路加固技术研究

文章对电路抗辐射的机理进行了研究,提出了几种提高数字电路抗辐射能力的方法:通过工艺控制减小辐射后的背栅阈值电压漂移,通过版图增加体接触、采用环型栅等结构提高单元的抗辐射能力,通过对电路关键节点的加固提高整体电路的抗辐射能力。为了验证加固方法的可靠性,设计了一款电路进行抗总剂量、抗瞬态剂量率、抗中子辐射、抗单粒子辐射等多种试验。通过辐照试验结果可以看到,采用抗辐照方法设计的电路具有较强的抗辐照能力,为今后抗辐照电路的研制和开发奠定了坚实的基础。     

基于SOI的抗辐射加固FPGA芯片

介绍抗辐射VS1000 FPGA芯片架构及其设计实现。改进的基于3输入查找表的多模式逻辑单元,与传统的基于4输入查找表相比,可以提高约12%的逻辑利用率。逻辑模块由两个逻辑单元组成,可以被配置成两种工作模式：LUT模式和分布式RAM模式。新颖的层次化布线通道模块和开关模块可以极大的提高布线资源的布通率。VS1000芯片包括392个可编程逻辑单元,112个用户IO以及与IEEE 1149.1兼容的边界扫描逻辑,采用0.5 um部分耗尽绝缘体上硅CMOS工艺全定制设计并流片。功能测试结果表明, 芯片软硬件能够成功配合且实现用户特定功能。抗辐照实验结果表明,抗总剂量水平超过100Krad(Si), 抗瞬态剂量率水平超过1.510¹¹rad(Si)/s,抗中子注入量水平达到110¹⁴ n/cm²。     

辐射加固SOI的SRAM基FPGA中IO模块阵列的设计与实现

本文中我们提出了一个用于辐射加固的SRAM基FPGA VS100的输入输出模块阵列,该FPGA用0.5微米部分耗尽SOI工艺设计,在中电集团58所流片。与FPGA的特性一致,每一个IO单元都由布线资源和两个IOC组成,IOC包括信号通路电路,可编程输入/输出驱动器和ESD保护网络组成。IO模块能用于不同的工作模式时,边界扫描电路既可以插入在输入输出数据路径电路和驱动器之间,也可以作为透明电路。可编程IO驱动器使IO模块能够用于TTL和CMOS电平标准。布线资源使得IO模块和内部逻辑之间的连接更加灵活和方便。辐射加固设计,包括A型体接触晶体管,H型体接触晶体管和特殊的D触发器的设计提高了抗辐射性能。ESD保护网络为端口上的高脉冲提供了放电路径,防止大电流损坏内部逻辑。这些设计方法可以适用于不同大小和结构的FPGA设计。IO单元阵列的功能和性能经过了功能测试和辐射测试的考验,辐照实验结果表明,抗总剂量水平超过100Krad(Si), 抗瞬态剂量率水平超过1.510¹¹rad(Si)/s,抗中子注入量水平达到110¹⁴ n/cm²。     

一种基于CMOS工艺的抗辐照A/D转换器

空间辐射对电子系统的损伤是航天设备发生故障的重要因素。A/D转换器是航天电子系统的关键器件之一,其抗辐射性能将直接影响航天设备的整体性能。基于标准0.35 μm CMOS工艺,设计了一种流水线型14位A/D转换器,从总体架构、关键核心单元、版图等方面进行抗辐照设计。辐照测试结果表明,该A/D转换器的抗总剂量能力达到1.0 kGy(Si),抗单粒子闭锁阈值达到37 MeV·cm²/mg,满足宇航电子系统的应用要求。     

一种抗辐射前置稳压高压电源

以一种高压电源的前置稳压电路作为研究对象,重点分析稳压控制电路的抗中子抗辐射能力。对导致中子辐照前后输出电压变化量的因素进行分析,并对关键元器件晶体管进行辐照效应分析和试验验证,提出了晶体管优化和采用达林顿晶体管结构2种加固措施。通过电路仿真和制作样机,得到在1 MeV等效中子2×1013 n/cm2中子注量后的仿真和实测结果与理论分析值相吻合,验证了抗辐射加固措施的有效性。     

InAs/InAsSb超晶格红外中/中波双色焦平面探测器研制

超晶格材料已经成为了第三代红外焦平面探测器的优选材料。双波段红外探测器能够通过对比两个波段内的光谱信息差异,对复杂的背景进行抑制,提高探测效果,在需求中尤为重要。本文开展了InAs/InAsSb超晶格中/中双色焦平面探测器设计及制备技术研究,从器件设计、材料外延、芯片加工等方面展开研究,制备了中心距30 μm的320×256 InAs/InAsSb二类超晶格中/中波双色焦平面探测器。器件短中波峰值探测率达到7.2×10¹¹ cm·Hz^1/2W^-1,中波峰值探测率为6.7×10¹¹ cm·Hz^1/2W^-1,短中波有效像元率为99.51%,中波为99.13%,获得了高质量的成像效果,实现中中双色探测。     

抗辐射加固CMOS基准设计

研究了基于0.5 μm互补金属氧化物半导体(CMOS)工艺的动态阈值MOS(DTMOS)晶体管的电流-电压特性曲线。与常规CMOS工艺PNP晶体管特性对比,得到了带隙电压基准电路设计准则;采用DTMOS和抗辐射设计加固技术,完成了抗辐射加固CMOS基准设计。辐照试验结果表明,设计的抗辐射加固CMOS基准的抗总剂量能力达到了300 krad(Si)。     

Influence of neutron radiation on breakdown voltage of silicon voltage limiter

Experimental study of silicon voltage limiters?? breakdown voltage dependence on neutron radiation was conducted. It revealed that with increase of radiation density from 0.1×10¹⁴ to 2×10¹⁵ N/cm² the breakdown voltage monotonously increases: the smaller the breakdown voltage, the higher radiation density is needed to provide nominal breakdown voltage. Test curves which may be used for stabilization (normalization) of the breakdown voltage for samples with technological variations are suggested.     

抗中子辐射加固超辐射发光二极管的研究

我们设计并制作了一种高性能的抗中子辐射的超辐射发光二极管。高能中子辐射后产生的位移损伤造成器件有源区内少子寿命减少,从而导致器件光输出功率的降低。通过理论分析可知高输出功率的超辐射发光二极管对中子辐射的敏感度较低。本文中的超辐射发光二极管的有源区采用了具有高量子效率和小体积有源区的InGaAsP/InP多量子阱结构,外延波导层采用了线性缓变折射率分别限制结构(GRIN-SCH),并设计和优化出了特殊波导吸收区和腔面减反射膜结构。辐射实验结果显示,在中子注量为6?10₁₃～1?10₁₄n/cm₂(1MeV)下,InGaAsP/InP多量子阱结构的超辐射发光二极管与双异质结结构相比具有更好的抗中子辐射性能。     

A comparison of the radiation tolerance of the STC bipolar,CMOS and merged bipolar/CMOS processes

This paper reports an assessment of the tolerance of STC’s bipolar, CMOS and ‘merged’ bipolar/CMOS processes to gamma total dose, dose rate and neutron fluence radiation effects. The objective of the assessment was to characterise process performance under worst case and near to worst case criteria when subjected to nuclear radiation up to the tactical level in accordance with BS 9000. Total dose irradiation was performed on the bipolar, CMOS and BiCMOS technologies with 9 Mrads (Si), 10-12 krads (Si) and 10-30 krads (Si) performance levels reported, respectively. Under dose rate conditions, transient upset, latch-up and photocurrent are reported with latch-up immunity reported for the bipolar 2 process and simultaneous latch-up and transient upset reported for both the bulk CMOS and BiCMOS processes. Neutron fluence testing was performed with the onset of failure for the CMOS reported at the 5 × 10¹⁴ neutrons/cm level and onset of failure for the bipolar and BiCMOS reported in the range 5 × 10¹⁴ to 5 × 10¹⁴ neutrons/cm².     

Specific features of transmutational doping of 30Si-enriched silicon crystals with phosphorus: Studies by the method of electron spin resonance

Electron spin resonance (ESR) is used to study the neutron transmutation doping of silicon crystals enriched with ³⁰Si isotope: phosphorus donors and radiation defects produced in the course of transmutational doping are observed. The ESR signals related to the phosphorus uncontrolled impurity in ³⁰Si before transmutational doping (the P concentration is ～10¹⁵ cm^?3) and phosphorus introduced by neutron irradiation with doses ～1 × 10¹⁹ cm^?2 and ～1 × 10²⁰ cm^?2 (the P concentrations are ～5 × 10¹⁶ and ～7 × 10¹⁷ cm^?3, respectively) are studied. As a result of drastic narrowing of the phosphorus ESR lines in ³⁰Si, the intensity of lines increased appreciably, which made it possible to measure the phosphorus concentration in the samples with a small volume (down to 10^?6 mm^?3). The methods for determining the concentration of P donors from hyperfine structure in the ESR spectra of isolated P atoms, exchange-related pairs, and clusters that consist of three, four, and more P donors are developed. In the region of high concentrations of P donors, in which case the hyperfine structure disappears, the concentration of P donors was estimated from the exchange-narrowed ESR line.     

The effect of neutron irradiation and annealing temperature on the electrical properties and lattice constant of epitaxial gallium nitride layers

Effect of irradiation with high reactor-neutron fluences (Φ = 1.5 × 10¹⁷-8 × 10¹⁹ cm⁻²) and subsequent heat treatments in the temperature range 100–1000°C on the electrical properties and lattice constant of epitaxial GaN layers grown on an Al₂O₃ substrate is considered. It is shown that, with the neutron fluence increasing to (1–2) × 10¹⁸ cm⁻², the resistivity of the material grows to values of about 10¹⁰ Ω cm because of the formation of radiation defects, and, with the fluence raised further, the resistivity passes through a maximum and then decreases to 2 × 10⁶ Ω cm at 300 K, which is accounted for by the appearance of a hopping conductivity via deep defects in the overlapping outer parts of disordered regions. With the neutron fluence raised to 8 × 10¹⁹ cm⁻², the lattice constant c increases by 0.38% at a nearly unchanged parameter a. Heat treatment of irradiated samples at temperatures as high as 1000°C does not fully restore the lattice constant and the electrical parameters of the material.     

Electronic properties of p-GaN(Mg) irradiated with reactor neutrons

The effect of irradiation with full-spectrum reactor neutrons and predominantly fast reactor neutrons (up to a fluence of 8 × 10¹⁸ cm^?2) on the electrical properties of epitaxial p-GaN(Mg) films at different initial doping levels (in the range of hole concentrations p = 10¹⁷–10¹⁹ cm^?3) is analyzed. It is found that neutron irradiation induces an increase in the resistivity of the initial material to 10¹⁰ Ω cm at 300 K. It is shown that, at high neutron fluences, the resistivity of the material decreases because of the hopping conduction of charge carriers over radiation defect states. The study of isochronous annealing at 100–1000°C reveals stages of donor-defect (100–300°C, 500–700°C, 750–850°C) and acceptor-defect (300–500°C, 650–800°C) annealing in the neutron-irradiated p-GaN(Mg) samples.     

High-efficiency (49%) and high-power photovoltaic cells based on gallium antimonide

High-efficiency GaSb-based photovoltaic cells designed for conversion of high-power laser radiation and infrared radiation of emitters heated by concentrated solar radiation are fabricated and studied. The maximum efficiency of conversion of the radiation with λ = 1680 nm was 49% at the photocurrent density of 50–100 A/cm² for the fabricated photovoltaic cells. The methods for reducing the losses at ohmic contacts to p-and n-GaSb are investigated. The minimum values of the specific resistance, (1–3) × 10^?6 Θ cm², of contact to p-GaSb with the doping level of 10²⁰ cm^?3 were obtained using the Ti/Pt/Au contact system. The minimum values of the specific contact resistance were (1–3) × 10^?6 Θ cm² in the case of n-GaSb with the doping level of 2 × 10¹⁸ cm^?3 if the Au(Ge)/Ni/Au and Au/Ni/Au contact systems are used.     

Operation of 4H-SiC high voltage normally-OFF V-JFET in radiation hard conditions: Simulations and experiment

Operation of high-voltage 4H-SiC vertical-JFET in radiation hard environment was investigated by simulation and experiment. Commercial 1700 V normally-OFF SiC JFETs in TO-247 package were irradiated with fast neutrons to fluences of 4.0 × 10¹⁴ cm^− 2 (1 MeV Si equivalent) and the effect of radiation on their characteristics was then thoroughly analyzed. Four degradation mechanisms were identified, of which the most important is the increase of JFETs ON-state resistance due to the mobility degradation and removal of carriers from transistor's light doped channel and drift regions. As a result, the JFET ON-state losses grow and, at fluences higher than 4 × 10¹⁴ cm^− 2, the low doped n-regions are fully compensated and transistor loses its functionality. On the contrary, irradiation slightly improves JFET's switching characteristics. The effect of neutron irradiation on operation of SiC V-JFET in a real application was then investigated on the step-UP 15 V/60 V DC-DC converter where the SiC JFET was used as an active switch. Converter characteristics were analyzed by means of the mixed-mode simulation using the developed 2D model of the neutron irradiated transistor. Results showed that the duty cycle of the PWM regulator is growing due to the increase in the voltage drop on the switching JFET. This effect, which is caused by the abovementioned increase the JFET's ON-state resistance, increases power dissipation and deteriorates converter efficiency. Finally, the effect of neutron irradiation on operation SiC V-JFET in the 850 V/24 V auxiliary flyback switching mode power supply was analyzed. We showed that the growth of the ON-state resistance increases transistor's conduction losses and decreases converter efficiency. Exceeding the fluence of 3.3 × 10¹⁴ cm^− 2 neutrons then causes JFET overheating and subsequent destruction.     

A slot resonators based quintuple band-notched Y-shaped planar monopole ultra-wideband antenna

A Y-shaped ultra-wideband (UWB) monopole antenna containing modified ground plane with five stop bands is presented. An inverted U-shaped slot and a C-shaped slot are placed on Y-shaped radiating patch to achieve two notched bands while three pairs of C-shaped slots are placed at different positions on modified ground plane to achieve three more notched bands. The proposed antenna is designed, fabricated and experimentally tested. The designed Y-shaped antenna has overall dimensions of 36 × 38 × 1.6 mm³ (0.34λ_l × 0.36 λ_l × 0.016 λ_l) and has impedance bandwidth 2.86–13.3 GHz at |S₁₁| < −10 dB level. Measured band notches are achieved at 3.75/5.43/7.87/8.62/9.87 GHz centre notched frequencies to eliminate worldwide interoperability for microwave access (WiMAX) band (3.45–4.0 GHz), wireless local area network (WLAN) band (5.15–5.90 GHz), X-band for satellite communication (6.77–8.00 GHz), ITU-8 band (8.3–9.1 GHz), and radio navigation (RN) band (9.3–10.6 GHz), respectively. Variation of slot parameter on individual band notch is also investigated. Omnidirectional radiation pattern for XZ-plane and dipole-like radiation pattern for YZ-plane are observed. Stable gain, variation of phase response in linear fashion and group delay <1.3 ns for whole ultra-wideband except at band notches is achieved.