Physical and electrical characterization of Hafnium oxide and Hafnium silicate sputtered films
Physical and electrical characterization of Hafnium oxide and Hafnium silicate sputtered films
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DOI：
10.1063/1.1417991
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发表时间：
2001-12-15
影响因子：
3.2
通讯作者：
Zabel, T
中科院分区：
文献类型：
--
作者：
Callegari, A;Cartier, E;Zabel, T
研究了氧化铪和硅酸铪薄膜作为SiO2栅极介质的可能替代品。在含少量氧的氩气气氛中，通过反应溅射从单个氧化铪靶中形成氧化铪薄膜。通过加入he稀释的硅烷气体来掺入硅，制备了硅酸铪。通过改变硅烷气体流量，将不同浓度的硅原子掺入到Hf氧化膜中。沉积是在22度和500度的温度下进行的。用核技术测定了薄膜的化学成分。光学反射率用于测量光学带隙。采用透射电子显微镜（TEM）研究了薄膜的形貌，并采用铝栅电容器测量了薄膜的电容电压和电流电压。透射电镜和电学测量结果表明，氧化溅射环境在Si界面处形成了约3 nm的SiO2界面层。这阻碍了等效厚度较小的Hf基高钾薄膜的生长。对界面氧化层进行校正后，发现Hf氧化物的介电常数从约21降低到约4-5，而Hf含量较低的铪硅酸盐（3 at）。% Hf和32 at。% Si)。光学带隙从氧化Hf的5.8 eV增加到硅酸盐薄膜的约7 eV。在1000℃退火和300℃金属化后退火后，在硅酸铪薄膜上测量到可忽略不计的平带电压位移，并观察到良好的界面钝化。但由于高温处理，漏电流增大。(C) 2001年美国物理研究所。
Hafnium oxides and hafnium silicate films were investigated as a possible replacement for the SiO2 gate dielectric. Hafnium oxide films were formed by reactive sputtering from a single Hf oxide target in a predominantly Ar atmosphere containing small additions of oxygen. Hafnium silicates were made by adding a He-diluted silane gas for Si incorporation. By changing the silane gas flow, different Si atomic concentrations were incorporated into the Hf oxide films. Depositions were performed with the substrate held at temperatures of 22 degreesC and 500 degreesC. The chemical composition of the films was determined with nuclear techniques. Optical reflectivity was used to measure the optical band gap. The film morphology was investigated by transmission electron microscopy (TEM) and the electrical properties were measured with capacitance-voltage and current-voltage measurements using aluminum gate capacitors. TEM and electrical measurement showed that a SiO2 interfacial layer of about 3 nm formed at the Si interface due to the oxidizing sputter ambient. This precluded the growth of Hf based high-K films with small equivalent thickness. After correction for the interfacial oxide layer, the dielectric constant was found to decrease from about 21 for Hf oxide to about 4-5 for the Hafnium silicates with low Hf content (3 at. % Hf and 32 at. % Si). The optical band gap was found to increase from 5.8 eV for Hf oxide to about 7 eV for the silicate films. After annealing at 1000 degreesC followed by a 300 degreesC postmetallization anneal, negligible flat band voltage shift were measured on hafnium silicate films and good interface passivation was observed. However, leakage currents increased due to the high temperature processing. (C) 2001 American Institute of Physics.