MEDICI 시뮬레이터를 이용한 DRAM의 Refresh 시간 개선에 관한 연구

• 영문명: A Study on Refresh Time Improvement of DRAM using the MEDICI Simulator
• 발행기관: 한국시뮬레이션학회
• 저자명: 이용희(Lee Yong-Hui) 이천희(Yi Cheon-Hee)
• 간행물 정보: 『한국시뮬레이션학회 논문지』제9권 제4호, 51~58쪽, 전체 8쪽
• 주제분류: 공학 > 기타공학
• 파일형태: PDF
• 발행일자: 2000.12.31

영문 초록

The control of the data retention time is a main issue for realizing future high density dynamic random access memory. The novel junction process scheme in sub-micron DRAM cell with STl(Shallow Trench Isolation) has been investigated to improve the tail component in the retention time distribution which is of great importance in DRAM characteristics. In this’ paper, we propose the new implantation scheme by gate-related ion beam shadowing effect and buffer-enhanced ⊿ Rp (projected standard deviation) increase using buffered N-implantation with tilt and 4X(4 times)-rotation that is designed on the basis of the local-field-enhancement model of the tail component. We report an excellent tail improvement of the retention time distribution attributed to the reduction of electric field across the cell junction due to the redistribution of N-concentration which is intentionally caused by Ion Beam Shadowing and Buffering Effect using tilt implantation with 4X-rotation. And also, we suggest the least requirements for adoption of this new implantation scheme and the method to optimize the key parameters such as tilt angle, rotation number, Rp compensation and Nd/Na ratio. We used MEDICI Simulator to confirm the junction device characteristics. And measured the refresh time using the ADVAN Probe tester.

목차

1. Introduction

2. Fabrications

3. Simulation with MEDICI

4. Conclusion

References