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Project - Semiconductor Radiation Effects Research

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Ohshima Team Leader

Project Leader Takeshi Ohshima

 

    Next-generation technologies, for example, new concept computers substitute for super computers to solve issues on limitation of miniaturization of semiconductors and increase of power consumption, perfect cryptographic communications for enhanced information securities and sensing with high accuracy and high sensitivity for research in life science and material science, are required for our life to be more comfortable, safer and more secure. Technologies based on quantum effects, thus, quantum computing, quantum information and quantum sensing, are expected to be solve those issues. In order to realize those technologies, qubits operating with robust and steady are indispensable. We study defect engineering using ion and electron beams for creation of defects which act as qubits and quantum sensors in wide bandgap semiconductors such as diamond and silicon carbide (Si).
    When semiconductor materials and devices are irradiated with radiations such as ion, electrons and gamma-rays, degradation of their characteristics, nondestructive and destructive malfunctions occur. For example, degradation of solar cells, flip-flop of memories and destruction of power devices in satellites are observed in space radiation environments. We study radiation response of solar cells and semiconductor devices to reveal the radiation degradation/malfunction mechanisms and in addition, establish radiation resistant technologies for development of long lifetime and highly reliable semiconductor devices that can be used in high radiation environments such as space, nuclear and accelerator facilities.

1.Defect Engineering of Wide Bandgap Semiconductors

In wide bandgap semiconductors such as diamond and Silicon Carbide (SiC), crystal defects called “Single Photon Source (SPS)” which emits one photon by the incidence of one photon can be created. We can realize quantum computers which have extremely higher calculation capability than current computers, very bright photonic devices of which size is well controlled in nano meter level and high sensitive quantum sensors (magnetic field and temperature etc.) if we can control spin and luminescence of defects acting as SPS. We study creation methodologies of SPSs, such as nitrogen-vacancy (NV) centers in diamond and silicon vacancy (VSi) in SiC, with high efficiency and high position accuracy using ion and electron beams, and quantum sensing using NV and VSi created in diamond and SiC, respectively. In addition, we explore new SPSs in GaN and BN as well as diamond and SiC using ion and electron beams.

 

2.Development of Extreme-Radiation-Resistant Electronics

Silicon Carbide (SiC) is known as a promising candidate for higher efficiency and lower energy consumption electronics than silicon. At the same time, SiC is expected to be applied to electronics used in extremely harsh environments, in which electronics based on silicon cannot be operated. To apply SiC to electronic devices for space and nuclear applications, we are developing SiC electronic devices with high reliability and long lifetime even in radiation environment. The electrical characteristics of devices such as LSI and solar cells used in space are affected by incidence of high energetic particles such as heavy ions, protons and electrons. As a result, the performance of such devices is degraded and/or the malfunction occurs. We study methodologies for the evaluation of radiation response of electronic devices and try to understand radiation degradation/malfunction mechanisms of electronic devices using the evaluation methodologies. Furthermore, we are developing radiation resistant technologies of electronic devices for space and nuclear applications.