Total Ionizing Dose Radiation Effects Research Articles

High-dose X-ray radiation induced MgO degradation and breakdown in spin transfer torque magnetic tunnel junctions

Magnetic tunnel junction (MTJ) with magnesium oxide (MgO) tunnel barrier is the core element of spin transfer torque-based magnetic random access memory. For the application in the space environment, the total ionizing dose radiation effects on MTJs need to be evaluated. In this work, the MTJs were exposed to X-ray radiation with different doses of up to 10 Mrad(Si). Measurements of current induced magnetization switching (CIMS) behavior of these MTJs were performed before and after radiation. The results show negligible changes in the tunneling magnetoresistance and current switching properties after 8 Mrad(Si) X-ray radiation. However, with a total dose of 9 Mrad(Si), a significant reduction in junction resistance of a fairly large number of MTJs was observed, which showed characteristics of MTJ breakdown. Moreover, in this study, all experimental MTJs became functionally disabled due to MgO breakdown under 10 Mrad(Si) X-ray radiation. The CoFeB/MgO/CoFeB interface microstructure was observed using X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy (HRTEM). Interfacial structural results indicate that the MgO degradation and breakdown behavior caused by X-ray ionizing radiation can give rise to radiation-induced oxygen vacancies across the tunnel barrier oxide layer.

Study of TID radiation effects on the breakdown voltage of buried P-pillar SOI LDMOSFETs with P-top region

This article presents the numerical investigation on the total ionizing dose (TID) radiation induced breakdown voltage shifting behavior of the silicon-on-insulator (SOI) buried P-pillar (BP) lateral double-diffused metal-oxide semiconductor (LDMOS) with a P-top region (TP). We validate the employed simulation models and structure parameters by the experiments of the 200 V rated SOI BP-LDMOS devices. We also discuss the breakdown voltage (BV) analysis of the SOI BPTP-LDMOS under different doping concentrations in the drift region. Because the lateral breakdown voltage can be effectively enhanced by the P-top region under STI layer, the SOI BPTP-LDMOS behaves a wider Nd window for rated 200 V compared with the SOI BP-LDMOS. Finally, we perform the numerical investigation of the TID radiation effect on the BV shift. Using the TID hardening design with the electric field modulation method, the hardened BPTP-LDMOS can achieve a significant improvement in the TID tolerance compared with the hardened SOI BP-LDMOS, from 575 to 775 krad(Si).

Total Ionizing Dose Radiation Effects Hardening Using Back-Gate Bias in Double-SOI Structure

To mitigate the total ionizing dose (TID) radiation impact, a new structure named double-silicon-on-insulator (DSOI) is introduced in this article. This new structure exhibits potential benefits of reducing the radiation-induced degradation effectively and independently, thanks to the additional electrode, which can be used to control the internal electrical field of the device. With this structure, the TID response and TID mitigation strategy using back-bias are discussed in DSOI nMOSFETs. Then, a 3-D TCAD simulation model is proposed to analyze the radiation-induced leakage path for each bias configuration. The impact of negative back-bias during irradiation on trapped charge distribution is given for both buried oxide layer and shallow trench isolation. At last, a 4k-bit static random access memory is used to verify the effectiveness of back-bias on TID-induced leakage current suppression at the circuit level. The experimental results show the possibility of using back-bias against TID threat.

Total Ionizing Dose Effects of the Color Complementary Metal Oxide Semiconductor (CMOS) Image Sensor at Different Bias

The experiments of total ionizing dose radiation effects on color CMOS image sensors at different biases were presented. Two bias conditions operated during 60Co γ irradiation, biased and unbiased. In the data processing, the data of four channels were extracted according to the sequence of Bayer array respectively to study the difference between each channel. The full well capacity and dark signal non-uniformity versus the cumulative doses were investigated. After γ-ray irradiation, the full well capacity of the samples decreased along with dark signal non-uniformity increased. Meanwhile, the descending amplitude of full well capacity was different in each channel, but the variation of dark signal non-uniformity was almost consistent. Moreover, the degradations of full well capacity and dark signal non-uniformity were more seriously under-biased.

不同偏置状态下4T-CMOS图像传感器的总剂量辐射效应

不同偏置状态下4T-CMOS图像传感器的总剂量辐射效应

Total Ionizing Dose Radiation Effects in the P-Type Polycrystalline Silicon Thin Film Transistors**Supported by the National Natural Science Foundation of China under Grant Nos 61574048 and 61204112, the Science and Technology Research Project of Guangdong Province under Grant Nos 2015B090912002 and 2014A030313656, and the Pearl River S&T Nova Program of Guangzhou.

The total ionizing dose radiation effects in the polycrystalline silicon thin film transistors are studied. Transfer characteristics, high-frequency capacitance-voltage curves and low-frequency noises (LFN) are measured before and after radiation. The experimental results show that threshold voltage and hole-field-effect mobility decrease, while sub-threshold swing and low-frequency noise increase with the increase of the total dose. The contributions of radiation induced interface states and oxide trapped charges to the shift of threshold voltage are also estimated. Furthermore, spatial distributions of oxide trapped charges before and after radiation are extracted based on the LFN measurements.

Total ionizing dose radiation effects on NMOS parasitic transistors in advanced bulk CMOS technology devices**Project supported by the National Natural Science Foundation of China (No. 11305126).

In this paper, total ionizing dose effect of NMOS transistors in advanced CMOS technology are examined. The radiation tests are performed at 60Co sources at the dose rate of 50 rad (Si)/s. The investigation's results show that the radiation-induced charge buildup in the gate oxide can be ignored, and the field oxide isolation structure is the main total dose problem. The total ionizing dose (TID) radiation effects of field oxide parasitic transistors are studied in detail. An analytical model of radiation defect charge induced by TID damage in field oxide is established. The I – V characteristics of the NMOS parasitic transistors at different doses are modeled by using a surface potential method. The modeling method is verified by the experimental I – V characteristics of 180 nm commercial NMOS device induced by TID radiation at different doses. The model results are in good agreement with the radiation experimental results, which shows the analytical model can accurately predict the radiation response characteristics of advanced bulk CMOS technology device.

Total ionizing dose radiation effects in foue-transistor complementary metal oxide semiconductor image sensors

Radiation effects on four-transistor (4 T) active pixel sensor complementary metal-oxide-semiconductor (CMOS) image sensor induced by -ray are presented. The samples are 4 megapixels resolution CMOS image sensor using 11 upm pitch high dynamic 4 T pixels. They are manufactured with 0.18 upm specialized CMOS image sensortechnology. Three samples have been exposed to 200 krad(Si) 60Co -ray with different biasing condition (1# is static-biased, 2# dynamic-biased, and 3# is grounded during irradiation), and the dose rate is 50 rad(Si)/s. The influences of radiation on full well charge capacity, dark current, and conversion gain of the device are investigated. Experimental result shows that the conversion gain is not sensitive to the ionizing radiation, and it is mainly determined by the CMOS digital or analog circuits. It is known that the total ionizing dose for induced degradation in deep submicron MOSFET is negligible and so there is almost no radiation effect on the digital or analog circuits exposed to the ionizing radiation. Therefore, conversion gain does not have obvious degradation after irradiation. While full well charge capacity has a degradation after irradiation, which is due to the change of TG channel doping profile induced by the radiation. As the dose increases, dark current increases rapidly. The main source of dark current in 4 T CMOS image sensor is the current from STI interface and TG-PD overlap region. Experimental result also shows that different from 3 T CMOS image sensor, there is no biasing effect in 4 T CMOS image sensor. This is because for the 4 T CMOS image sensor most of the degradation come from STI interface and TG-PD overlap region, while biasing condition almost has no influence on both ofthem.

Degradation of CMOS APS Image Sensors Induced by Total Ionizing Dose Radiation at Different Dose Rates and Biased Conditions

The experiments of total ionizing dose radiation effects on CMOS APS image sensors at the dose rates of 50.0 and 0.2 rad(Si)/s were presented. The CMOS APS image sensors were manufactured using the standard <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$0.35 - \mu \hbox{m}$</tex></formula> CMOS technology that had a typical gate-oxide thickness of 7.0 nm. The samples were divided into two groups, with one group biased and the other unbiased during <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$^{60}{\rm Co}\gamma $</tex> </formula> irradiation. When the samples were exposed to the total dose of 200 krad(Si), only one investigated device was still exposed up to the highest total dose of 800 krad(Si), and functional failure was observed. The dark signal ( <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${K_{\rm D}}$</tex></formula> ), dark signal non-uniformity (DSNU), noise ( <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${V_{\rm N}}$</tex></formula> ), saturation output signal voltage ( <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${V_{\rm S}}$</tex></formula> ), and dynamic range (DR) versus the total doses were investigated. The tendency for <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$K_{\rm D}$</tex></formula> , DSNU, and <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${V_{\rm N}}$</tex></formula> to increase at 50.0 rad(Si)/s is larger than that at 0.2 rad(Si)/s. The degradation mechanisms of CMOS APS image sensors were analyzed. The room temperature annealing tests were performed at 24 h, 48 h, and 168 h with different biased conditions after irradiation.

Study of total ionizing dose radiation effects on enclosed gate transistors in a commercial CMOS technology

This paper studies the total ionizing dose radiation effects on MOS (metal-oxide-semiconductor) transistors with normal and enclosed gate layout in a standard commercial CMOS (compensate MOS) bulk process. The leakage current, threshold voltage shift, and transconductance of the devices were monitored before and after γ-ray irradiation. The parameters of the devices with different layout under different bias condition during irradiation at different total dose are investigated. The results show that the enclosed layout not only effectively eliminates the leakage but also improves the performance of threshold voltage and transconductance for NMOS (n-type channel MOS) transistors. The experimental results also indicate that analogue bias during irradiation is the worst case for enclosed gate NMOS. There is no evident different behaviour observed between normal PMOS (p-type channel MOS) transistors and enclosed gate PMOS transistors.

VHDL-AMS Modeling of Total Ionizing Dose Radiation Effects on CMOS Mixed Signal Circuits

A hierarchical method for total dose effects simulation of large mixed signal circuits using VHDL-AMS is described. Simplified behavioral models (or macro-models) of small sub-circuits replace SPICE-level circuits. The behavioral models describe the electrical circuit behavior and its dependence on the radiation dose. The behavioral models of sub-circuits can be assembled into complex mixed signal circuits. As a result, the computational cost is reduced significantly compared to conventional SPICE-based methods. The VHDL-AMS method also allows bias-dependent total dose degradation to be coupled to the circuit and operational conditions. Simulation accuracy remains sufficient to determine critical performance metrics of the circuit as the circuit performance degrades with dose.

Radiation effects and hardening of MOS technology: devices and circuits

Total ionizing dose radiation effects on the electrical properties of metal-oxide-semiconductor devices and integrated circuits are complex in nature and have changed much during decades of device evolution. These effects are caused by radiation-induced charge buildup in oxide and interfacial regions. This paper presents an overview of these radiation-induced effects, their dependencies, and the many different approaches to their mitigation.