夢幻記憶體：非揮發性的磁性記憶體

MRAM: a Promising Non-Volatile Memory

磁性隨機存取記憶體（MRAM）因為其讀寫速度迅速、具非揮發性、易於與半導體製程整合等優點，一直被視為是未來舉足輕重的記憶體。本文將詳細介紹：從早期的藉由磁場運作類型、近期剛開始商業化生產的自旋轉移力矩（STT）運作型，一直到自旋軌道力矩（SOT）型，MRAM運作模式也從間接地由電流給予磁場，轉變為直接給予非常短暫的脈衝就可以讀寫運作，達到快速讀寫的目標。本文也會著墨於SOT型MRAM的一些運作挑戰，及其逐漸地被克服的解決方案。 Magnetic random access memory(MRAM) has been regarded as an important memory because of its fast readwrite operation, non-volatility and capability of integration to current semiconductor process. In this article, we will go through different operating mechanisms of MRAM: toggle-mode type, recent spin-transfer torque(STT) type and spin-orbit torque(SOT) type. The operating mechanism changes from applying magnetic fi eld to only a single, fast pulse, and thus accomplishes the fast read-write process. This article will also describe about the challenges of SOT, and corresponding solutions.