激光定位深亚微米CMOS SRAM单粒子翻转敏感区

The pulsed laser facility for SEU sensitivity mapping is utilized to study the SEU sensitive regions of a 0.18/zm CMOS SRAM cell. Combined with the device layout micrograph, SEU sensitivity maps of the SRAM cell are obtained. TCAD simulation work is performed to examine the SEU sensitivity characteristics of the SRAM cell. The laser mapping experiment results are discussed and compared with the electron micrograph information of the SRAM cell and the TCAD simulation results. The results present that the test technique is reliable and of high mapping precision for the deep submicron technology device.     

Nickel silicide as a contact material for submicron CMOS devices

Nickel monosilicide (NiSi) is an attractive alternative to the currently used silicides for the coming generations of deep submicron complementary metaloxide-semiconductor (CMOS) devices. This silicide material has a resistivity, which is comparable to that of TiSi₂ or CoSi₂, but consumes less silicon for its formation. The silicide silicon interface is relatively planar and, unlike TiSi₂, its resistivity does not change with the linewidth for narrow lines. However, the thermal stability of NiSi is relatively poor at the currently used temperatures during process integration. Recent studies have shown that the stability of these films could be increased substantially through the small addition of alloy elements, which do not increase the resistivity of the NiSi film. Morever, it has been demonstrated that the addition of a small amount of alloy elements significantly reduces diode leakage, possibly due to the suppression of silicide spike formation as a result of alloy addition. This paper will present and discuss the details of these experimental results.     

Complementary-SCR ESD protection circuit with interdigitatedfinger-type layout for input pads of submicron CMOS IC's

A new ESD protection circuit with complementary SCR structures and junction diodes is proposed. This complementary-SCR ESD protection circuit with interdigitated finger-type layout has been successfully fabricated and verified in a 0.6 μm CMOS SRAM technology with the LDD process. The proposed ESD protection circuit can be free of VDD-to-VSS latchup under 5 V VDD operation by means of a base-emitter shorting method. To compensate for the degradation on latching capability of lateral SCR devices in the ESD protection circuit caused by the base-emitter shorting method, the p-well to p-well spacing of lateral BJT's in the lateral SCR devices is reduced to lower its ESD-trigger voltage and to enhance turn-on speed of positive-feedback regeneration in the lateral SCR devices. This ESD protection circuit can perform at high ESD failure threshold in small layout areas, so it is very suitable for submicron CMOS VLSI/ULSI's in high-pin-count or high-density applications     

Experimental characterization of the diode-type polysilicon loadsfor CMOS SRAM

Experimental characterization of the diode-type n⁺-p-n ⁺ poly-Si loads for SRAM applications demonstrates that the resistance of the structure and its response to the bit-line voltages are dominated by such properties of the parasitic thin-film transistor associated with this device as fixed positive charge and `gate' oxide thickness. Topographical effects observed in this study are interpreted in terms of the thickness variation of a dielectric overlaying the poly-Si feature and the fixed positive charges present in this dielectric in the vicinity of the poly-Si surface     

Leakage scaling in deep submicron CMOS for SoC

In this paper, we demonstrate the effects of CMOS technology scaling on the high temperature characteristics (from 25°C to 125°C) of the four components of off-state drain leakage (I_off ) (i.e. subthreshold leakage (I_sub), gate edge-direct-tunneling leakage (I_EDT), gate-induced drain-leakage (I_GIDL), and bulk band-to-band-tunneling leakage (I_B-BTBT)). In addition, the high temperature characteristics of I_off with reverse body bias (V_B) for the further reduction of the standby leakage are also demonstrated. The discussion is based on the data measured from three CMOS logic technologies (i.e., low-voltage and high performance (LV), low-power (LP), and ultra-low-power (ULP)) and three generations (0.18 μm, 0.15 μm, and 0.13 μm). Experiments show that the optimum V_B, which minimizes I_off, is a function of temperature. The experiments also show that for CMOS logic technologies of the next generations, it is important to control I_B-BTBT and I_GIDL by reducing effective doping concentration and doping gradient. It seems that in order to conform on-state gate leakage (I_G-on) and I_EDT specifications and to retain a 10-20% performance improvement at the same time, it is indispensable to use high-quality and high-dielectric-constant materials to reduce effective oxide thickness (EOT). The role of each leakage component in SRAM standby current (I_SB) is also analyzed     

Intrinsic leakage in deep submicron CMOS ICs-measurement-based testsolutions

The high leakage current in deep submicron, short-channel transistors can increase the stand-by power dissipation of future IC products and threaten well established quiescent current (I_DDQ)-based testing techniques. This paper reviews transistor intrinsic leakage mechanisms. Then, these well-known device properties are applied to a test application that combines I_DDQ and ICs maximum operating frequency (F_max) to establish a novel two-parameter test technique for distinguishing intrinsic and extrinsic (defect) leakages in ICs with high background leakage. Results show that I_DDQ along with F_max can be effectively used to screen defects in high performance, low V_T (transistor threshold voltage) CMOS ICs     

CMOS/SOI 64Kb静态随机存储器

对一种CMOS/SOI 64Kb静态随机存储器进行了研究,其电路采用8K×8的并行结构体系．为了提高电路的速度,采用地址转换监控(Address-Translate-Detector,ATD)、两级字线(Double-Word-Line,DWL)和新型的两级灵敏放大等技术,电路存取时间仅40ns;同时,重点研究了SOI静电泄放(Electrostatic-Discharge,ESD)保护电路和一种改进的灵敏放大器,设计出一套全新ESD电路,其抗静电能力高达4200—4500V．SOI 64Kb CMOS静态存储器采用1.2μm SOI CMOS抗辐照工艺技术,芯片尺寸为7.8mm×7.24mm．     

CMOS APS crosstalk characterization via a unique submicron scanning system

This work introduces a novel way for CMOS APS crosstalk (CTK) determination and prediction based on our unique Submicron Scanning System (SSS) measurements. It enables the crosstalk magnitude determination, the tracking of its main causes, and can be used as a predictive tool for design optimization. A pronounced crosstalk asymmetry within the array which was revealed by the measurements is analyzed and modeled. The result points out that CMOS APS crosstalk is mostly affected by the specific pixel architecture and the pixels arrangement within the array.     

CMOS/SOI64Kb静态随机存储器

对一种 CMOS/ SOI6 4Kb静态随机存储器进行了研究 ,其电路采用 8K× 8的并行结构体系 .为了提高电路的速度 ,采用地址转换监控 ( Address- Translate- Detector,ATD)、两级字线 ( Double- Word- L ine,DWL)和新型的两级灵敏放大等技术 ,电路存取时间仅 40 ns;同时 ,重点研究了 SOI静电泄放 ( Electrostatic- Discharge,ESD)保护电路和一种改进的灵敏放大器 ,设计出一套全新 ESD电路 ,其抗静电能力高达 42 0 0— 45 0 0 V.SOI6 4KbCMOS静态存储器采用 1.2 μm SOI CMOS抗辐照工艺技术 ,芯片尺寸为 7.8m m× 7.2 4mm     

An SEU-Resilient SRAM Bitcell in 65-nm CMOS Technology

This paper presents an SEU-resilient 12 T SRAM bitcell. Simulation results demonstrate that it has higher critical charge than the traditional 6 T cell. Alpha and proton testing results validate that it has a lower soft error rate compared to the reference designs for all data patterns and supply voltage levels. The improvement in SEU tolerance is achieved at the expense of 2X area penalty.     

A 4-Mb CMOS SRAM with a PMOS thin-film-transistor load cell

A 4-Mb (512 K words by 8-b) CMOS static RAM (SRAM) with a PMOS thin-film transistor (TFT) has been developed. The RAM can obtain a much larger data-retention margin than a conventional high-resistive load-type well by using the PMOS TFT as a memory cell load. An internal voltage down-converter architecture with an external supply voltage-level sensor not only realizes a highly reliable 0.5-μm MOS transistor operation but also a sufficiently low standby-power dissipation characteristic for data battery-backup application. A self-aligned equalized level sensing scheme can minimize the sensing delay for a local sense amplifier to drive a large load capacitance of a global sensing bus line. The RAM is fabricated using a 0.5 μm, triple-poly, and double-aluminum with dual gate-oxide-thickness CMOS process technology. The RAM operates under a single 5-V supply voltage with 23-ns typical address access time and 20- and 70-mA operation current at 10 and 40 MHz, respectively     

CMOS layout design of the hysteresis McCulloch-Pitts neuron

A McCulloch-Pitts neuron is the simplified neuron model which has been successfully used for many optimisation problems. The neural network with the hysteresis property can suppress the oscillatory behaviours of neural dynamics so that the convergence time is shortened. In this paper, digital CMOS layout design of the hysteresis McCulloch-Pitts neuron is presented. Based on simulation results using the hysteresis McCulloch-Pitts binary neuron model, a 6-bit fixed point 2's complement arithmetic was adopted for the calculation of the input U of each neuron. Each neuron needs 204 transistors and requires a 399 lambda *368 lambda layout area using the MOSIS scalable CMOS/bulk (SCMOS) VLSI technology with 2 mu m rule of P well, double level metal. Layout design of the hysteresis McCulloch-Pitts neuron chip was completed, and fabrication of the chip and the design for the test circuit for the fabricated CMOS VLSI chip are underway at present.<>     

90nm CMOS工艺SRAM的优化及应用

提出了一种优化的SRAM,它的功耗较低而且能够自我修复.为了提高每个晶圆上的SRAM成品率,给SRAM增加冗余逻辑和E-FUSE box从而构成SR SRAM.为了降低功耗,将电源开启/关闭状态及隔离逻辑引入SR SRAM从而构成LPSR SRAM.将优化的LPSR SRAM64K×32应用到SoC中,并对LPSR SRAM64K×32的测试方法进行了讨论.该SoC经90nm CMOS工艺成功流片,芯片面积为5.6mm×5.6mm,功耗为1997mW.测试结果表明:LPSR SRAM64K×32功耗降低了17.301%,每个晶圆上的LPSRSRAM64K×32成晶率提高了13.255%.     

A high speed,precision voltage buffer in a submicron CMOS process

A new buffer architecture was introduced by Comer and Comer (1998, International Journal of Electronics, 84, 345). This buffer uses an active feedback network based on a transconductance amplifier. An implementation of the new buffer was done in a CMOS process. The buffer was intended for the output stage of a 10-bit video digital-to-analogue converter. The circuit was fabricated on the American Microsystems 0.6 μm process. Design specifications called for a gain accuracy of 0.1%, an offset voltage shift of no more than 1mV over a commonmode input range of 50% of supply voltage and a bandwidth of 500MHz. The actual circuit showed a gain error of less than 0.1%, a common-mode offset variation of less than 2mV, and a bandwidth of 450MHz.     

采用0.18μm CMOS工艺的多端口SRAM设计

文章详细描述了一种采用0.18μmCMOS工艺的多端口单位线SRAM设计方法。与传统的6TSRAM结构相比,在写数据时增加了写节点充电信号,降低了内核CMOS器件设计的复杂度;在读数据时增加了额外的读位线放电电路,减少了读数据延迟;同时读写数据均采用电流模式,降低功耗,较好的解决了多端口SRAM存取数据时存在的问题。     

Performance comparison of CNFET- and CMOS-based 6T SRAM cell in deep submicron

This paper presents a performance comparison of a carbon nanotube-based field effect (CNFET)- and CMOS-based 6T SRAM cell at the 32 nm technology node. HSPICE simulations, carried out using Berkeley predictive technology model (BPTM), show that for a cell ratio and pull-up ratio of 1, CNFET-based 6T SRAM cell provides an improvement of 21% in read static noise margin (SNM) at VDD=0.4 V. The speed of CNFET cell is 1.84× that of CMOS cell. The standby leakage of CNFET cell is 84% less than CMOS cell. The process parameter variation results in 1.2% change in the read SNM of CNFET cell as compared with a wide variation of around 10.6% in CMOS cell.     

90nm CMOS工艺SRAM的优化及应用

提出了一种优化的SRAM,它的功耗较低而且能够自我修复.为了提高每个晶圆上的SRAM成品率,给SRAM增加冗余逻辑和E-FUSE box从而构成SR SRAM.为了降低功耗,将电源开启/关闭状态及隔离逻辑引入SR SRAM从而构成LPSR SRAM.将优化的LPSR SRAM64K×32应用到SoC中,并对LPSR SRAM64K×32的测试方法进行了讨论.该SoC经90nm CMOS工艺成功流片,芯片面积为5.6mm×5.6mm,功耗为1997mW.测试结果表明:LPSR SRAM64K×32功耗降低了17.301%,每个晶圆上的LPSRSRAM64K×32成晶率提高了13.255%.     

Design of a Process Variation Tolerant Self-Repairing SRAM for Yield Enhancement in Nanoscaled CMOS

In nanoscaled technologies, increased inter-die and intra-die variations in process parameters can result in large number of parametric failures in an SRAM array, thereby, degrading yield. In this paper, we propose a self-repairing SRAM to reduce parametric failures in memory. In the proposed technique, on-chip monitoring of leakage current and/or delay of a ring oscillator is used to determine the inter-die process corner of an SRAM die. Depending on the inter-die Vt shift, the self-repair system selects the proper body bias to reduce parametric failures. Simulations using predictive 70-nm device show that the proposed self-repairing SRAM improves design yield by 5%-40%. A test-chip is designed and fabricated in IBM 0.13-mum CMOS technology to successfully demonstrate the operation of the self-repair system.     

Detailed investigation of active CMOS mixers noise in submicron technology

A unified noise figure expression incorporating the thermal noise and flicker noise has been proposed for active CMOS mixers. Based on the derived conversion functions with output resistance effect, the noise transforming factors for different stages are numerically computed to rigorously describe the noise output. The subthreshold conductance has also been taken into account by utilizing the latest continuous noise model and the simplified MOSFET I-V model. As a result, the frequency-dependent characteristic of noise expression is of competency for explaining the flicker noise mechanism, thus can be directly applied to active CMOS mixers with any IF characteristics. And good agreement is obtained between simulations and measurements.     

A 300-MHz 4-Mb wave-pipeline CMOS SRAM using a multiphase PLL

A 4-Mb (64 k×64) synchronous wave-pipeline CMOS SRAM is fabricated by 0.25-μm CMOS technology. Multiphase active pulse control (MPAC) enables fully random 300 MHz operation at 2.5 V, resulting in a bandwidth of 2.4 GB/s. The pulse is generated by multiphase PLL (MPPLL) using an array oscillator with current consumption of 7.5 mA