下一代存储材料

Core Viewpoint - Oxide semiconductors are gaining attention as potential materials for next-generation storage architectures, offering compatibility with back-end-of-line (BEOL) processes and improvements in key metrics such as durability, data retention, and scalability [1][29]. Group 1: Recent Advances and Challenges - Significant progress has been made in n-type oxide semiconductors, including IGZO, InWO, InSnO, and InO, which are suitable for BEOL storage unit access transistors due to their ultra-low leakage characteristics and compatibility with low thermal budget processes below 400°C [3][4]. - The article reviews the latest advancements in oxide semiconductor-based storage unit technologies and discusses the challenges faced in material and device development to meet performance requirements [4][29]. Group 2: Storage Device Types - Three main types of BEOL-compatible oxide semiconductor-based memory are summarized: 1. DRAM-like 1T-1C storage structure using ultra-low leakage n-type oxide semiconductors [3][4]. 2. Capacitorless 2T-0C gain cell memory, which includes configurations of n-n and n-p [20][21]. 3. Ferroelectric memory utilizing n-type oxide semiconductors combined with Hf-based ferroelectric dielectrics [26][27]. Group 3: Performance Metrics - A recent demonstration of a 1T-1C storage chip using n-type oxide semiconductor transistors achieved a random cycle time of 8 ns and a retention time of 128 ms at a VDD of 0.75 V, showcasing excellent reliability at 85°C [6][17]. - The durability test results for the 1T-1C storage chip indicated a bit error rate (BER) of less than 1 ppm after 10¹⁴ cycles at 85°C, confirming the robustness of the device [16][17]. Group 4: Challenges in Device Optimization - Key challenges include optimizing contact resistance (RC) in short-channel devices to achieve high drive current (ION) for ultra-low voltage operation, controlling threshold voltage (VT) to suppress leakage while maintaining circuit functionality, and improving process and passivation control to enhance reliability [8][10][12]. - The presence of hydrogen in n-type oxide systems is highly sensitive to reliability performance, necessitating surface treatment and passivation methods to minimize hydrogen content and prevent diffusion into the channel [14][16]. Group 5: P-Type Oxide Semiconductor Development - Research on p-type oxide semiconductors remains limited and challenging, with SnO emerging as a promising candidate due to its thermal compatibility and unique electronic structure [21][22]. - Recent advancements in SnO devices fabricated using wafer-compatible processes demonstrated an ION/IOFF ratio of approximately 10⁴ and a mobility of about 1 cm²/V·s, indicating progress in p-type oxide semiconductor technology [22][24]. Group 6: Future Prospects - The integration of oxide semiconductor channels with ferroelectric materials presents unique challenges, including weak erase phenomena and durability degradation due to oxygen vacancy diffusion [26][27]. - The potential for oxide semiconductor-based storage technologies to reshape storage system architectures and meet the growing demands of data center workloads is significant, but breakthroughs in p-type oxide materials are essential for expanding applications in next-generation storage and logic solutions [29].