热处理温度对Hf_(0.5)Zr_(0.5)O_(2)薄膜结构和性能的影响

Effect of thermal processing temperature on structure and properties of Hf_(0.5)Zr_(0.5)O_(2)thin films

新型氧化铪基铁电薄膜由于其优越的极化特性、良好的尺寸微缩性以及与新型CMOS工艺的高度兼容性,成为了近年来的研究热点。采用原子层沉积方法(ALD)制备的Hf_(0.5)Zr_(0.5)O_(2)(HZO)薄膜,经过快速热处理(RTP),在上下电极的应力作用下会产生铁电性。本文研究了不同热处理温度对HZO薄膜结构和性能的影响,内容包括:沉积态的HZO薄膜为非晶态,经过快速热处理后,薄膜晶化;对比快速热处理温度为500℃和600℃的电容结构器件单元性能,发现600℃退火后HZO铁电器件的剩余极化更大,矫顽电场更大;对500℃和600℃热处理的器件截面进行结构分析,发现500℃热处理后会有四方相和正交相出现,热处理温度600℃时出现单斜相和正交相。

The HfO_(2)-based ferroelectric thin film has become a research hotspot in recent years because of its excellent polarization characteristics,miniaturization and high compatibility with complementary metal oxide semiconductor(CMOS)technology.Hf_(0.5)Zr_(0.5)O_(2)(HZO)thin films deposited by atomic layer deposition(ALD)show the ferroelectricity after rapid thermal process(RTP)with the stress of top and bottom electrodes.In this paper,the effects of different rapid thermal processing temperatures on the structure and properties of HZO film were studied.It was found that the deposited HZO film is amorphous,and it crystallized through rapid thermal process.Comparing the ferroelectric test results of capacitor units with rapid thermal process temperature of 500℃and 600℃,it is found that the residual polarization(P_(r))and coercive electric field(E_(c))of HZO capacitor unit are larger when the HZO capacitor units annealed at 600℃.Besides,the cross-section structure of the capacitor units with rapid thermal process temperature of 500℃and 600℃were analyzed.Results imply that tetragonal phases and orthonormal phases appear through rapid thermal processing at 500℃,while monoclinic phases and orthonormal phases appear after annealing at 600℃.