초록 ▼

○ 본 先기획연구의 목적은 Logic-in-Memory에 탑재가 가능한 스핀궤도결합 소재 연구개발 방안을 도출하고, 향후 심층 연구개발단계의 연구목표, 범위, 내용 및 추진전략을 체계화하고 핵심기술별 특허포트폴리오 확보방안을 도출하는 것임
○ 대상 기술은 기존의 반도체 구조가 갖는 단점을 극복할 수 있는 비휘발성 메모리와 논리소자를 일체화하여 저전력, 고속, 저면적 로직용 메모리 구현이 가능하게 할 것으로 예상됨
○ 先기획연구에서는 과학적 연구기획 방법론을 적용하여 전략 연구개발 분야 도출을 위한 4개의 탐색연구를 수행하

○ 본 先기획연구의 목적은 Logic-in-Memory에 탑재가 가능한 스핀궤도결합 소재 연구개발 방안을 도출하고, 향후 심층 연구개발단계의 연구목표, 범위, 내용 및 추진전략을 체계화하고 핵심기술별 특허포트폴리오 확보방안을 도출하는 것임
○ 대상 기술은 기존의 반도체 구조가 갖는 단점을 극복할 수 있는 비휘발성 메모리와 논리소자를 일체화하여 저전력, 고속, 저면적 로직용 메모리 구현이 가능하게 할 것으로 예상됨
○ 先기획연구에서는 과학적 연구기획 방법론을 적용하여 전략 연구개발 분야 도출을 위한 4개의 탐색연구를 수행하였으며, 11명의 기획위원이 총 11회의 기획회의를 실시하여, 전략과제 설정, 타당성 조사, 문헌특허 수집 및 분석, 기술트리, 연구개발 로드맵 및 원천특허 포트폴리오를 도출하였음
○ 先기획연구 수행을 통해 4개 핵심기술을 도출하였으며, 스핀궤도토크 소재개발의 구체적 연구목표 (예, 스핀홀 각도 > 0.98, 수직이방성 > 7.0x10⁶ erg/cm³,기록안정성 계수 > 40) 및 추진체계를 포함하는 연구과제 계획 작성하였음

Abstract ▼

Ⅳ.Research Results
□Current status of domestic and international research and development
○Targeted creative materials technology of Spin-Orbitronics is to be implemented in low power, high speed, and high density Logic-in-Memory by maximizing spin-orbit coupling in ferromagnet-nonmagnet or f

Ⅳ.Research Results
□Current status of domestic and international research and development
○Targeted creative materials technology of Spin-Orbitronics is to be implemented in low power, high speed, and high density Logic-in-Memory by maximizing spin-orbit coupling in ferromagnet-nonmagnet or ferromagnet–ferromagnet interfaces
○ Spin-orbit coupling materials which were firstly discovered by a french group in 2011, are being rapidly developed by research groups in US, France, and Japan through national R&D investment.
○ Current research is rather focused on identification of the physical origin of spin-orbit torque (SOT) and will be extended to find various SOT materials and device applications
○ Necessity of new materials research methodologies such as theory-based materials design and simultaneous and multiple characterization to reduce time and resource for the optimization of SOT materials
○ Domestic technology in Spin-Orbitronics materials research is of global level, and developed results will be commercialized by transferring them to domestic semiconductor industries
□ Feasibility Studies
○ Enhancement of predictive capability of first principles calculation
- Magnetic states originated from asymmetric exchange energy cannot be accurately calculated by conventional ab initio calculation
- Developed calculation technique to describe non-collinear spin state and calculated Dzyaloshinskii-Moriya Interaction (DMI) coefficient in Co(1 monolayer)/Pt(3 monolayers)
- Obtained DMI coefficient of 1.04 mJ/m², which is confirmed to be comparable to experimental value of 0.8 ~ 1.3 mJ/m² using Brillouine light scattering (BLS)
○ Manipulation of spin-orbit coupling
- Confirmed the possibility of new materials research methodologies (combinatorial and multiple characterization) to overcome long optimization time of SOT materials with various parameters
- Fabricated wedge-shaped specimen of Pd/Co/Pd structure, where Pd thickness and oxygen content are simultaneously varied over a single wafer
- Preformed multiple characterization of SOT-induced effective field and magnetic property in SOT array using electric and X-ray magnetic circular dichroism (XMCD)
○ New materials for simple SOT switching:
- Necessity of removing the external magnetic field in conventional SOT switching for nano-scale device application
- Measured effective SOT field from antiferromagnetic IrMn in Ta/IrMn/CoFeB/MgO, of which magnitude is comparable to conventional heavy metal of Ta
- Induced exchange bias field by aligning antiferromagnetic order, which allows the SOT switching without external magnetic field
○ Circuit simulation for validation of target figures in R&D project aims
- Justification is required proper materials specifications for Logic-in-Memory application
- Determined the materials specification by comparing calculated operation power and area of SOT-based Logic-in-Memory with those of SRAM
- Required spin Hall angle of 0.98 and switching speed of 1 ns for SOT-based memory with energy consumption, less than 23% of conventional SRAM
□ Research and Development (R&D) objectives and implementation strategies
○ R&D Objectives: Development of Spin-Orbitronic materials for ultra low power (<34 fJ/bit), high speed (< 1 ns) Logic-in-Memory
○ R&D Objectives
- Core technology (Magnetic tunnel junction): Ferromagnet(FM)/non-magnetic metal(NM) materials simultaneously satisfying the following requirements of spin Hall angle > 0.98, thermal stability factor > 40, Heat treatment stability > 400°C, andfield-free switching
- The strategy is to conduct research on both the main technology and two kinds of future technology simultaneously from the first phase of the project. The future technology, as expectedly, is technologically immature at present, but its impact can be potentially high and its R&D competition can be low, making it easier to secure key patents in advance.
- Future technology 1 (Domain wall materials): FM/NM materials simultaneously satisfying the following requirements of spin Hall angle > 0.3, DMI coefficient > 1 erg/cm², and thermal stability factor > 40
- Future technology 2 (Skyrmion materials): FM/NM materials simultaneously satisfying the following requirements of spin Hall angle > 0.1, DMI coefficient > 4 erg/cm², and thermal stability factor > 40
○R&D strategies based on new materials research methodology
1. Strategies for theoretical study
- Prediction of spin Hall angle and DMI coefficient, and magnetic anisotropy: Design FM/NM materials with a proper spin Hall angle, DMI coefficient, and magnetic anisotropy for each core technology using band structure calculation to find out anti-crossing point and/or band-filling effect
- Proper description of current-induced magnetic switching, domain wall or Skyrmion motion, and thermal stability using micromagnetic simulation
- Precise prediction of power consumption of SOT-based memories using SPICE circuit simulation
3. Strategies for materials processing
- Fast material optimization of FM/NM systems designed by theoretical calculation using combinatorial experiment and multiple characterization
- Control interface properties in FM/NM structure using ion radiation after confirmation by simulation to control spin Hall angle and DMI coefficient
- Introduction of new materials of antiferromagnet or new structures to achieve SOT switching without external magnetic field
4. Strategies for multiple property characterization
- Develop measurement techniques to obtain reliable SOT properties of spin Hall angle and DMI coefficient
- Determine the correlation among SOT parameters using multiple characterization techniques to propose ideas for better SOT materials
- Establish standard measurement system and personal network for SOT materials which allows a fast and precise identification of SOT materials properties, effectively reducing time and cost for optimization of spin-orbitronic materials

목차 Contents

• 표지 ... 1
• 제출문 ... 2
• 보고서 요약서 ... 3
• 요약문 ... 4
• SUMMARY ... 9
• CONTENTS ... 14
• 목차 ... 16
• 제1장 先기획연구 개요 ... 17
• 1.先기획연구의 목적,필요성 및 범위 ... 17
• 제2장 기술개발 현황 및 조사·분석 ... 22
• 1.국내·외 기술개발 현황 ... 22
• 2.선행 연구 조사·분석 및 시사점 ... 36
• 제3장 기술개발 목표 및 내용 ... 68
• 1.원천특허 포트폴리오 ... 68
• 2.연구개발내용 및 범위 ... 72
• 3.기존 기술과의 차별성 및 원천성 ... 98
• 4.국가 소재 R&D 전략과의 연계성 및 부합성 ... 107
• 5.先연구내용 및 결과 ... 109
• 제4장 先기획연구 활동 추진 내용 ... 124
• 1.先기획연구 추진 체계 ... 124
• 2.先기획연구 방법론 ... 127
• 3.先기획연구 활동 내용 ... 129
• 제5장 기대성과 및 활용 계획 ... 156
• 1.기대성과 ... 156
• 2.상용화 예상 분야 ... 158
• 3.경제성 분석 ... 163
• 제6장 참고문헌 ... 171
• 별첨1 先기획연구 활동 회의록 ... 176
• 별첨2 산학연 컨설팅 의견서 ... 210
• 끝페이지 ... 211