擁有低溫快速退火條件的HfAlO鐵電記憶體

Abstract

非揮發記憶體元件廣泛的應用在消費性電子產品上。過去幾十年來，FRAM因為擁有很快的速度和較低的功率消耗，因此在市場上擁有重要的地位，而鐵電材料即為FRAM的核心。然而，隨著CMOS元件不斷的微縮，使得我們迫切的尋找新的鐵電材料來取代傳統的鐵電材料如PZT和SBT，傳統的鐵電材料無法微縮也不適用於CMOS製程。以HfO2為基底的鐵電材料且擁有著金屬-鐵電-絕緣體-矽基板結構的鐵電記憶體，由於有著高密度、速度快、非揮發性和非破壞性讀取的特性，更甚者，它能夠微縮且相容於CMOS製程技術，所以是很有潛力的新興鐵電材料。 在此篇論文中，我們對MFM和MFIS結構的電容進行製程和電特性量測，並且成功的製做出HfO2為基底的鐵電場效電晶體(FeFETs)擁有TaN/HAO/SiO2/P-sub的結構，其中HAO當作鐵電層，SiO2則是當作緩衝層。鐵電電晶體在低退火溫度650 oC下，就擁有較好的鐵電特性，Id-Vg的記憶窗大概有0.4V且次臨界斜率的值是130mV/dec。

Nonvolatile memory devices are enormously used in consumer electronics. Ferroelectric materials have been attracted attention for past decades since these are the core of ferroelectric random acces memory(FRAM) which play important role in the market due to fast speed and much lower power consumption. However, as the CMOS devices scale down continuously, it is imperative that we find out new ferroelectric materials to replace traditional one such as PZT and SBT which can’t scale and is not applicable for CMOS process. The HfO2-base ferroelectric field effect transistors (FeFETs) with metal-ferroelectrical-insulator-silicon(MFIS) structure become a promising candidate due to the high density, high speed, nonvolatile and non-destructive read. Moreover, it can scale down and integrate into the CMOS technology. In this thesis, we illustrated the fabrication and electrical characteristics of MFIS capacitors and MFM capacitors and then we successfully fabricated HfO2-based MFIS FETs with a TaN/HAO/SiO2/P-sub, in which HAO is used as the ferroelectric gate and SiO2 is used as the buffer layer. The FeFETs annealed at the 650oC have better ferroelectric properties. The memory window of Id-Vg is about 0.4V and Subthreshold slope is 130mV/dec.