Abstract: The structural properties and local contact potential difference of Au on Si(111)-(7×7) surface are studied by the homemade ultra-high vacuum non-contact Kelvin probe force microscope. Although scanning tunneling microscopy has been widely used to study the metal- adsorbed semiconductor surfaces on an atomic scale, the tunnel current measured by scanning tunneling microscopy is easy to lead the charge states to accidentally switch in the measurement process, and it is limited only to the observation of metal and semiconductor surfaces. Kelvin probe force microscope allows us to directly measure the charges at different positions of various flat surfaces by local contact potential difference on an atomic scale, which has become a more convenient and accurate means of charge characterization. In this paper, the topography and local contact potential difference of Au adsorbed Si(111)-(7×7) surface are measured on an atomic scale by Kelvin probe force microscope at room temperature, and the corresponding adsorption model and first principle calculation are established. The differential charge density distribution of the stable adsorption position of Au/Si(111)-(7×7) is obtained, and the local contact potential energy difference relationship of the stable adsorption position of Au on Si surface is given, The mechanism of charge transfer between Au atom and Si(111)-(7×7) surface during adsorption is analyzed. The experimental results show that at room temperature, single Au atom will form triangular delocalized adsorption state in the half unit cell of Si(111)-(7×7). The delocalized adsorption state is due to the fact that the moving speed of a single Au atom in the HUC is faster than the scanning speed of Kelvin probe force microscope, and the local contact potential difference measurement of Au/Si(111)-(7×7) adsorbed surface can effectively identify Au and Si atoms. Obviously, this research is of great significance in promoting the development of surface charge precision measurement, and is expected to provide some insights into the charge properties of metal adsorbed semiconductor surfaces.

Abstract: It has been nearly 110 years since the discovery of superconductors, and more than 30 years since the discovery of high temperature superconductors (HTS). Great progress has been made in the application of superconducting electronics in the last two decades. HTS microwave devices have shown much higher perfomance than the traditional ones and have found their ways to the industry applications in mobile communication, radar, and special communication applications. Owing to the ultrahigh sensitivity to magnetic fields and currents, superconducting quantum interference devices (SQUIDs) have been used as the irresplacible sensors in geological surveying, magnetic resonanc imaging, biomagnetic imaging, and other areas. The sensitivity of superconducting radiation detectors such as superconducting SIS mixer, superconducting hot electron bolometer, superconducting transition edge sensor, superconducting nanowire single photon detector, and superconducting microwave kinetic inductance detector are near the quantum limitation. They are now key technology in geophysics, astrophysics, quantum information science, biomedicine, and so on. Superconducting Josephson parametric amplifier has become a key element for superconducting quantum computing. Superconducting integrated circuit has been included in the international roadmap for devices and systems, and shows that having the potential to become one of the mainstreams for post-Moore information processing technology. In metrology, superconducting Josephson effect and Josephson junction array devices have been widely used in the redefinition of quantum voltage reference and basic units of the International system of Units. Superconducting electronics plays an important role in the current quantum information technology boom, which in turn promotes the development of superconducting electronics. This review will brief introduce the research and application of superconducting electronics in China in recent years.

Abstract: Magnetic imaging technology based on photo-emission electron microscopy (PEEM) has become an important and powerful tool for observing the magnetic domain in spintronics. The PEEM can get access to real-time imaging with high spatial resolution and is greatly sensitive to the spectroscopic information directly from the magnetic films and surfaces through photoemission process with variable excitation sources. Moreover, the breakthrough in the deep ultraviolet (DUV) laser technology makes it possible to realize domain imaging without the limitation of synchrotron radiation facilities or the direct excitation of photoelectrons due to the high enough photon energy of the source in the current threshold excitation study. In this review article, the deep ultraviolet photo-emission electron microscopy system is first introduced briefly. Then, a detailed study of the magnetic domain observation for the surface of L1〈sub〉0〈/sub〉-FePt films by the DUV-PEEM technique is presented, where a spatial resolution as high as 43.2 nm is successfully achieved. The above results clearly indicate that the DUV-PEEM reaches a level equivalent to the level reached by X-ray photoemission imaging technique. Finally, a series of recent progress of perpendicular FePt magnetic thin films obtained by the DUV-PEEM technique is provided in detail. For example, a stepped Cr seeding layer is used to form the large-area epitaxial FePt films with (001) and (111) two orientations, where magnetic linear dichroism (MLD) with large asymmetry is observed in the transition area of two phases. The signal of MLD is 4.6 times larger than that of magnetic circular dichroism. These results demonstrate that the magnetic imaging technology based on DUV-PEEM with excellent resolution ability will potentially become an important method to study magnetic materials in the future.

Abstract: Bi〈sub〉2〈/sub〉Te〈sub〉3〈/sub〉-based alloys have been long regarded as the materials chosen for room temperature thermoelectric (TE) applications. With superior TE performances, Bi〈sub〉2〈/sub〉Te〈sub〉3〈/sub〉-based bulk materials have been commercially used to fabricate TE devices already. However, bulk materials are less suitable for the requirements for applications of flexible or thin film TE devices, and therefore the thin film materials with advanced TE properties are highly demanded. Comparing with bulk materials and P-type Bi〈sub〉2〈/sub〉Te〈sub〉3〈/sub〉-based thin films, the TE properties of N-type Bi〈sub〉2〈/sub〉Te〈sub〉3〈/sub〉-based thin films have been relatively poor so far and need further improving for practical applications. In this study, a series of N-type Bi〈sub〉2〈/sub〉Te〈sub〉3〈i〉–〈/i〉〈/sub〉〈sub〉〈i〉x〈/i〉〈/sub〉Se〈sub〉〈i〉x〈/i〉〈/sub〉 thin films is prepared via magnetron sputtering method, and their structures can be precisely controlled by adjusting the sputtering conditions. Preferential layered growth of the Bi〈sub〉2〈/sub〉Te〈sub〉3–〈/sub〉〈sub〉〈i〉x〈/i〉〈/sub〉Se〈sub〉〈i〉x〈/i〉〈/sub〉 thin films along the (00l) direction is achieved by adjusting the substrate temperature and working pressure. Superior electrical conductivity over 10〈sup〉5〈/sup〉 S/m is achieved by virtue of high in-plane mobility. combining the advanced Seebeck coefficient of Bi〈sub〉2〈/sub〉Te〈sub〉3〈/sub〉-based material with superior electrical conductivity of highly oriented Bi〈sub〉2〈/sub〉Te〈sub〉3–〈/sub〉〈italic/〉〈i〉〈sub〉x〈/sub〉〈/i〉Se〈sub〉〈i〉x〈/i〉〈/sub〉 thin film, a high power factor (PF) of the optimal Bi〈sub〉2〈/sub〉Te〈sub〉3–〈/sub〉〈sub〉〈i〉x〈/i〉〈/sub〉Se〈sub〉〈i〉x〈/i〉〈/sub〉 thin film can be enhanced to 42.5 μW/(cm·K〈sup〉2〈/sup〉) at room temperature, which is comparable to that of P-type Bi〈sub〉2〈/sub〉Te〈sub〉3〈/sub〉-based thin film and bulk material.

Abstract: 〈sec〉 Based on the wide-spectrum neutron beam (covering thermal neutrons and 〈i〉E〈/i〉 〉 10 MeV neutrons, with maximum energy of 1.6 GeV) provided by the China Spallation Neutron Source (CSNS), this paper focuses on the single event effect study of 14 nm FinFET large-capacity SRAM and 65 nm planar process SRAM device, using combined techniques of irradiation experiment, reverse analysis, and Monte-Carlo neutron transport simulation. The aim is to reveal the effect of integrated circuit process changing on the sensitivity of neutron induced single-bit and multiple-bit upsets (MBU), and to analyze the inner mechanisms, including the distribution of secondary particles in the sensitive volume, the characteristics of deposited charges, etc. 〈/sec〉〈sec〉 The results show that compared with the 65 nm device, single event upset (SEU) cross section of the 14 nm FinFET device, induced by 〈i〉E〈/i〉 〉 10 MeV neutrons, is reduced by about 40 times, while the MBU ratio increases from 2.2% to 7.6%, which is due to the reduction of sensitive volume size of the 14 nm FinFET device (80 nm × 30 nm × 45 nm), pitch, and critical charge (0.05 fC). The main forms of MBU are double-bit upset, triple-bit upset and quadruple-bit upset. Unlike the phenomenon that the 65 nm device is immune to thermal neutrons, the use of the 〈sup〉10〈/sup〉B element near M0 in the 14 nm FinFET device causes it to present the thermal neutron sensitivity to a certain extent. The SEU cross section induced by thermal neutrons is about 4.8 times smaller than that induced by 〈i〉E〈/i〉 〉 10 MeV neutrons. 〈/sec〉〈sec〉 Based on the device cross-section and memory area images obtained from the reverse analysis, a device model is established and neutron transport simulation based on Geant4 toolkit is carried out. The 〈i〉E〈/i〉 〉 10 MeV neutrons result in abundant secondary particle distribution in the sensitive volume of the device, covering n, p into even W. The neutron energy and presence or absence of the W plug near the sensitive volume have an importantinfluence on the type and probability of secondary particles in the sensitive volume. The analysis and calculations show that a large number of high-〈i〉Z〈/i〉 secondary particles with long range and large LET values generated by high-energy neutrons in the sensitive volume of the device are the inducement of MBU, and SEUs mainly result from the contribution of light ions such as p, He, and Si. 〈/sec〉

Abstract: As a major component in the air, nitrogen emits fluorescence when it interacts with intensive laser field. The fluorescence comes from the first negative band system (〈inline-formula〉〈tex-math id="M7"〉\begin{document}${{\rm{B}}^{{2}}}\Sigma _{\rm{u}}^{{ + }} \to {{\rm{X}}^{{2}}}\Sigma _{\rm{g}}^{{ + }}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M7.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M7.png"/〉〈/alternatives〉〈/inline-formula〉 transition) of 〈inline-formula〉〈tex-math id="M8"〉\begin{document}${\rm{N}}_{{2}}^{{ + }}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M8.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M8.png"/〉〈/alternatives〉〈/inline-formula〉 and the second positive band system (〈inline-formula〉〈tex-math id="M9"〉\begin{document}${{\rm{C}}^{{3}}}\Pi _{\rm{u}}^{{ + }} \to {{\rm{B}}^{{3}}}\Pi _{\rm{g}}^{{ + }}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M9.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M9.png"/〉〈/alternatives〉〈/inline-formula〉 transition) of 〈inline-formula〉〈tex-math id="M10"〉\begin{document}${{\rm{N}}_{{2}}}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M10.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M10.png"/〉〈/alternatives〉〈/inline-formula〉. Under the action of high-intensity femtosecond laser, 〈inline-formula〉〈tex-math id="M11"〉\begin{document}${{\rm{N}}_{{2}}}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M11.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M11.png"/〉〈/alternatives〉〈/inline-formula〉 can be directly photo-ionized into 〈inline-formula〉〈tex-math id="M12"〉\begin{document}${\rm{N}}_{{2}}^{{ + }}{{(}}{{\rm{B}}^{{2}}}\Sigma _{\rm{u}}^{{ + }})$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M12.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M12.png"/〉〈/alternatives〉〈/inline-formula〉, which results in fluorescence emission of 〈inline-formula〉〈tex-math id="M13"〉\begin{document}${\rm{N}}_{{2}}^{{ + }}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M13.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M13.png"/〉〈/alternatives〉〈/inline-formula〉. In the process of femtosecond laser filament formation, the dynamic processes such as ionization and excitation of nitrogen molecules are affected by the laser intensity distribution and laser polarization direction. The products show different distributions in the propagation direction and radial space, which, in turn, affects its light emission. Therefore, it is necessary to further ascertain its generation mechanism through the spatial distribution of nitrogen fluorescence. In this experiment, the spatial distribution of the nitrogen fluorescence emission generated by linearly polarized femtosecond laser pulse filaments in air is measured. By changing the polarization direction of the laser to study the distribution of nitrogen fluorescence in the radial plane, it is found that the fluorescence emission of 〈inline-formula〉〈tex-math id="M14"〉\begin{document}${\rm{N}}_2^ + $\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M14.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M14.png"/〉〈/alternatives〉〈/inline-formula〉 is more intense in the direction perpendicular to the laser polarization, while it is weaker in the direction parallel to the laser polarization. The nitrogen fluorescence emission has the same intensity in all directions. The ionization probability of a linear molecule depends on the angle between the laser polarization direction and the molecular axis, which is maximum (minimum) when the angle is 〈inline-formula〉〈tex-math id="M15"〉\begin{document}${{{0}}^{\rm{o}}}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M15.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M15.png"/〉〈/alternatives〉〈/inline-formula〉(〈inline-formula〉〈tex-math id="M16"〉\begin{document}${{9}}{{{0}}^{\rm{o}}}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M16.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M16.png"/〉〈/alternatives〉〈/inline-formula〉). The 〈inline-formula〉〈tex-math id="M17"〉\begin{document}${{\rm{N}}_{{2}}}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M17.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M17.png"/〉〈/alternatives〉〈/inline-formula〉 gas is more likely to be ionized in the laser polarization direction, the nitrogen molecular ions 〈inline-formula〉〈tex-math id="M18"〉\begin{document}${\rm{N}}_{{2}}^{{ + }}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M18.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M18.png"/〉〈/alternatives〉〈/inline-formula〉 and electrons are separated in the direction parallel to the laser polarization. Therefore, more ions (〈inline-formula〉〈tex-math id="M19"〉\begin{document}${\rm{N}}_{{2}}^{{ + }}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M19.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M19.png"/〉〈/alternatives〉〈/inline-formula〉) are generated in the direction parallel to the laser polarization, and the fluorescence emission of 〈inline-formula〉〈tex-math id="M20"〉\begin{document}${\rm{N}}_{{2}}^{{ + }}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M20.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M20.png"/〉〈/alternatives〉〈/inline-formula〉 is more intense. Along the propagation direction of the laser, it is found that the fluorescence of 〈inline-formula〉〈tex-math id="M21"〉\begin{document}${{\rm{N}}_{{2}}}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M21.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M21.png"/〉〈/alternatives〉〈/inline-formula〉 appears before the fluorescence of 〈inline-formula〉〈tex-math id="M22"〉\begin{document}${\rm{N}}_2^ + $\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M22.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M22.png"/〉〈/alternatives〉〈/inline-formula〉 and disappears after the fluorescence of 〈inline-formula〉〈tex-math id="M23"〉\begin{document}${\rm{N}}_{{2}}^{{ + }}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M23.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M23.png"/〉〈/alternatives〉〈/inline-formula〉 has vanished. This is due to the fact that 〈inline-formula〉〈tex-math id="M24"〉\begin{document}${{\rm{N}}_{{2}}}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M24.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M24.png"/〉〈/alternatives〉〈/inline-formula〉 can be ionized into 〈inline-formula〉〈tex-math id="M25"〉\begin{document}${\rm{N}}_{{2}}^{{ + }}{{(}}{{\rm{B}}^{{2}}}\Sigma_{\rm{u}}^{{ + }})$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M25.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M25.png"/〉〈/alternatives〉〈/inline-formula〉 at the position of high enough laser intensity, thus emitting fluorescence of 〈inline-formula〉〈tex-math id="M26"〉\begin{document}${\rm{N}}_2^ + $\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M26.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M26.png"/〉〈/alternatives〉〈/inline-formula〉. However, the laser energy is not enough to ionize nitrogen at the beginning and end of laser transmission, but it can generate 〈inline-formula〉〈tex-math id="M27"〉\begin{document}${\rm{N}}_2^ * $\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M27.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M27.png"/〉〈/alternatives〉〈/inline-formula〉, which emits nitrogen fluorescence through the process of intersystem crossing 〈inline-formula〉〈tex-math id="M28"〉\begin{document}${\rm{N}}_2^*\xrightarrow{{{\rm{ISC}}}}{{\rm{N}}_2}({{\rm{C}}^3}\Pi _{\rm{u}}^ + )$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M28.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M28.png"/〉〈/alternatives〉〈/inline-formula〉. The spatial distribution of nitrogen fluorescence emission during femtosecond laser filament formation shows that in the case of short focal length, the intersystem crossing scheme can explain the formation of 〈inline-formula〉〈tex-math id="M29"〉\begin{document}${{\rm{N}}_{{2}}}{{(}}{{\rm{C}}^{{3}}}\Pi _{\rm{u}}^{{ + }})$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M29.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20201704_M29.png"/〉〈/alternatives〉〈/inline-formula〉. This research is helpful in understanding the mechanism of nitrogen fluorescence emission.

Abstract: Ion trap system is one of the main quantum systems to realize quantum computation and simulation. Various ion trap research groups worldwide jointly drive the continuous enrichment of ion trap structures, and develop a series of high-performance three-dimensional ion trap, two-dimensional ion trap chip, and ion traps with integrated components. The structure of ion trap is gradually developing towards miniaturization, high-optical-access and integration, and is demonstrating its outstanding ability in quantum control. Ion traps are able to trap increasingly more ions and precisely manipulate the quantum state of the system. In this review, we will summarize the evolution history of the ion trap structures in the past few decades, as well as the latest advances of trapped-ion-based quantum computation and simulation. Here we present a selection of representative examples of trap structures. We will summarize the progresses in the processing technology, robustness and versatility of ion traps, and make prospects for the realization of scalable quantum computation and simulation based on ion trap system.

Abstract: Ion trap system is one of the main quantum systems to realize quantum computation and simulation. Various ion trap research groups worldwide jointly drive the continuous enrichment of ion trap structures, and develop a series of high-performance three-dimensional ion trap, two-dimensional ion trap chip, and ion traps with integrated components. The structure of ion trap is gradually developing towards miniaturization, high-optical-access and integration, and is demonstrating its outstanding ability in quantum control. Ion traps are able to trap increasingly more ions and precisely manipulate the quantum state of the system. In this review, we will summarize the evolution history of the ion trap structures in the past few decades, as well as the latest advances of trapped-ion-based quantum computation and simulation. Here we present a selection of representative examples of trap structures. We will summarize the progresses in the processing technology, robustness and versatility of ion traps, and make prospects for the realization of scalable quantum computation and simulation based on ion trap system.

Abstract: Indirectly driven inertial confinement fusion implosions using a three-step-shaped pulse are performed at a 100 kJ laser facility. At late time of the pulse, deposition of laser energy and distribution of X-ray radiation are significantly disturbed by motion of gold plasma in the original gas-filled cylindrical hohlraum with gold wall. As a result, owing to the lack of X-ray drive at the equator of the capsule, an unacceptable oblate implosion is produced. In the I-raum modified from the above cylindrical hohlraum, the initial positions of outer laser spots and gold bubbles are appropriately shifted to modify the disturbed radiation distribution due to plasma evolution, resulting in a spherically symmetric drive on the capsule. In the implosion shots with almost the same drive pulse, owing to improved symmetry, an spherical hotspot is observed in the new I-raum, and YOS (the ratio of measured neutron yield over simulated one) is up to 30%, while an oblate hotspot is observed in the cylinder, and YOS is only 13%. The simulation calculations and experimental measurements show that the I-raum can be used to significantly reduce the impact of gold bubble expansion in the three-step-shaped pulse driven implosion, which helps to tune the drive and implosion symmetry, and to improve its over-all performance.

Abstract: The damage mechanism of the total ionizing dose (TID) effect of SiGe heterojunction bipolor transistar (SiGe HBT) is explored by using three-dimensional simulation of semiconductor device (TCAD).In the simulation, the trapped charge defects are introduced into different locations of oxidationin SiGe HBT to simulate the TID effect. Then the degradation characteristics of the forward Gummel characteristic and the reverse Gummel characteristic of the device are analyzed, and the TID damage law of SiGe HBT is obtained. Finally, the simulation results are compared with the 〈sup〉60〈/sup〉Co γ irradiation test results, showing that the trapped charges introduced by TID irradiation in SiGe HBT device mainly affect the Si/SiO〈sub〉2〈/sub〉 interface near the p-n junction, resulting in the change in the depletion region of the p-n junction and the increase of carrier recombination. Eventually, the base current increases and the gain decreases. The trapped charges generated in the EB spacer oxide layer mainly affect the forward Gummel characteristics, and the trapped charges in the LOCOS isolation oxide layer are the main factor causing the reverse Gummel characteristics to degrade. The experimental results on 〈sup〉60〈/sup〉Co γ irradiation under different biases are consistent with those from the total dose effect damage law of SiGe HBT obtained by numerical simulation analysis.