本文關(guān)鍵詞：鉿基柵介質(zhì)薄膜的PEALD制備及界面調(diào)控研究　出處：《北京有色金屬研究總院》2017年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 鉿基高k柵介質(zhì) PEALD 摻雜 等離子體處理 Si SiGe ETSOI MOSFET

【摘要】：隨著CMOS集成電路的快速發(fā)展,集成電路的基本單元MOSFET器件的幾何尺寸不斷縮小。在這種條件下,器件的柵介質(zhì)性能、溝道遷移率以及短溝道控制力、可靠性等方面隨之遇到嚴(yán)峻挑戰(zhàn)。特別是進(jìn)入16納米及以下節(jié)點以后,CMOS器件需要有更高介電常數(shù)的柵介質(zhì)薄膜、高遷移率的溝道材料以及新型器件結(jié)構(gòu)。因此本文以鉿基氧化物柵介質(zhì)材料為研究對象,探索了 PEALD制備工藝和不同元素?fù)诫s對鉿基薄膜高k柵介質(zhì)材料性能的影響,并考察鉿基高k柵介質(zhì)在ETSOI MOSFET器件中應(yīng)用的可行性。具體研究內(nèi)容如下:(1)研究了 PEALD制備工藝對HfO_2薄膜的材料性能影響。實驗表明,以O(shè)_2等離子·體為氧前驅(qū)體條件下,Ar作為載氣較N_2作為載氣所制備的HfO_2薄膜質(zhì)量更優(yōu)。其主要原因是N_2載氣在等離子條件下參與HfO_2薄膜的沉積反應(yīng)并以Hf-N-O和Hf-N化學(xué)鍵形式存在,造成HfO_2薄膜的固定缺陷密度增大以電學(xué)性能衰退;此外實驗在Ar載氣條件下,分別以O(shè)_2等離子體、H2O和O3作為氧前驅(qū)體制備HfO_2薄膜,研究發(fā)現(xiàn)相同物理厚度下的薄膜,其飽和電容密度相當(dāng)。O3等離子體制備的HfO_2薄膜具有最小固定缺陷濃度。(2)研究了Ti、Zr、Gd摻雜對鉿基薄膜化學(xué)組分及電學(xué)性能的影響。結(jié)果顯示,Ti、Zr、Gd摻雜均能顯著增加HfO_2薄膜的介電常數(shù),分別能夠達(dá)到39、20.4和22.4。其中,Ti摻雜對介電常數(shù)的影響最大。盡管Zr的摻雜降低了鉿基薄膜與Si襯底的導(dǎo)帶偏移量,但是Zr含量為10at%的ZrO_2-HfO_2(ZHO)非晶薄膜具有良好的電學(xué)特性。Gd摻雜有效地抑制了 Gd2O3-HfO_2(GHO)/Si界面層的生成,使得薄膜的固定缺陷密度和漏電流密度有顯著下降。(3)采用PEALD等離子體方法處理HfO_2/SiO_2界面和HfO_2/SiGe界面,研究了等離子體對界面的鈍化作用。研究發(fā)現(xiàn)N_2等離子體處理HfO_2/SiO_2界面后,N原子占據(jù)氧空位和O原子間隙,減少SiO_2界面層的氧空位并對鈍化O原子,同時N原子在SiO_2表面形成Si-N鍵抑制HfO_2與SiO_2原子相互擴(kuò)散,有效降低HfO_2薄膜O原子的缺失,堆棧結(jié)構(gòu)的固定缺陷濃度從3.2×1012cm~(-2)下降到2.5×1012cm~(-2),從而漏電流密度從1.1×10-3A/cm~2下降到3.2×10-6A/cm~2,飽和電容密度從1.36μF/cm~2提高到1.49μF/cm~2,并且保持良好的電學(xué)性能穩(wěn)定性;在HfO_2薄膜沉積之前,以N_2/H2等離子體處理SiGe表面后,N原子以Ge-N和Si-N鍵的形式存在,減少了 SiGe界面氧化物和固定缺陷濃度,漏電流密度從2.4×10-4A/cm~2 下降到 4.6×10-6A/cm~2,飽和電容密度從 1.53μF/cm~2 增大到 1.73μF/cm~2,相應(yīng)的EOT從1.82nm下降到1.64nm,并且0.3MHz到1MHz的C-V曲線頻散從9.7%下降到8.7%,降低了 HfO_2/SiGe的界面態(tài)密度。(4)采用PEALD制備工藝在SiGe/Si襯底上沉積GHO薄膜,研究N_2等離子體逐層退火GHO薄膜對GHO/SiGe堆棧結(jié)構(gòu)化學(xué)組分和電學(xué)性能的影響。研究發(fā)現(xiàn)Gd摻雜可以抑制鉿基薄膜氧空位的生成,減少GHO/SiGe界面氧化物的生成,使鉿基薄膜的組分更符合化學(xué)計量比,提高了薄膜的飽和電容密度,降低了漏電流密度;研究發(fā)現(xiàn)通過N_2等離子體逐層對GHO薄膜進(jìn)行原位退火,N原子占據(jù)GHO薄膜的氧空位位置,降低了 GHO薄膜的固定缺陷密度,同時N原子以Ge-N和Si-N形式鈍化界面,減少了界面氧化物的生成和界面態(tài)密度,薄膜的漏電流密度從1.9×10-5A/cm~2下降到2×108A/cm~2。(5)將TiO_2-HfO_2(THO)高k柵介質(zhì)體系應(yīng)用于16/14nm ETSOI CMOS工藝器件,探索了 THO高k薄膜在小尺寸(Lg=25nm)新型結(jié)構(gòu)器件的可行性。研究發(fā)現(xiàn),以THO作為柵介質(zhì)薄膜的ETSOI MOSFET比以HfO_2作為柵介質(zhì)薄膜的ETSOIMOSFET具有更優(yōu)異的開關(guān)性能、短溝道控制能力和溝道遷移率。其中以THO為柵介質(zhì)薄膜的ETSOIpMOSFET器件主要性能有,開態(tài)電流密度為4.63×1O-4A/μm,關(guān)態(tài)電流密度為1.5×10-8A/μm,開關(guān)比為3.1×104,跨導(dǎo)值為2.67mA/V,DIBL 為 53mV/V,SS 為 65mV/dec,器件空穴遷移率為28cm~2V-1s-1;通過THO代替HfO_2作為柵介質(zhì)薄膜,可以提高器件整體性能,滿足器件進(jìn)一步縮小的需求。
[Abstract]:With the rapid development of integrated circuit CMOS, geometry MOSFET basic unit of integrated circuit devices shrinking. In this condition, the gate dielectric properties of the device, channel mobility and short channel control, then the reliability challenges encountered and so on. Especially after entering the 16 nm node and below, need CMOS devices a gate dielectric film with higher dielectric constant, high mobility channel materials and new device structure. Therefore, hafnium based oxide gate dielectric material as the research object, to explore the preparation process of PEALD and doping different elements influence on the performance of HF based thin films with high k dielectric materials, and investigate the feasibility of the application high k gate dielectric in ETSOI MOSFET devices. The specific contents are as follows: (1) study the effects of preparation process of PEALD on properties of HfO_2 films. Experimental results show that the O_2 plasma and body for oxygen The body under the condition of Ar as the carrier gas is N_2 as the carrier gas HfO_2 film preparation quality is better. The main reason is the deposition of HfO_2 films on N_2 carrier gas in plasma under the condition of Hf-N-O and Hf-N and existed in the form of chemical bond, fixed defect density of HfO_2 films increases to cause electrical performance decline; in addition, the carrier gas under the condition of Ar, H2O and O_2 respectively in plasma, O3 as oxygen precursor for the preparation of HfO_2 thin film thickness under the same physical findings, HfO_2 thin film and its saturation density of capacitance is the equivalent of.O3 plasma prepared with the minimum fixed defect concentration. (2) of Ti, Zr, Gd doping and electrical properties of hafnium based film chemical group. The results showed that Ti, Zr, Gd doping can significantly increase the dielectric constant of HfO_2 thin films can reach 39,20.4 and 22.4. respectively, the Ti doping on the dielectric constant of the greatest influence. Although Zr Doping reduces the conduction band offset hafnium based film and Si substrate, but the content of Zr is 10at% ZrO_2-HfO_2 (ZHO) doped amorphous thin film with good electrical properties of.Gd effectively inhibited the formation of /Si Gd2O3-HfO_2 (GHO) interface layer, the fixed defect density of thin films and the leakage current density decreased significantly (3.) using PEALD plasma method of HfO_2/SiO_2 interface and HfO_2/SiGe interface, the passivation effect of plasma on the interface. The study found that N_2 plasma treatment, HfO_2/SiO_2 interface, N atoms and O atoms occupy the oxygen vacancy gap, reducing the oxygen vacancy less SiO_2 interface layer and the passivation of O and N atoms, atomic Si-N bond formation inhibition of HfO_2 and SiO_2 the diffusion of atoms on the surface of SiO_2, reduce the loss of HfO_2 thin film of O atoms, the stack structure of fixed defect concentration from 3.2 * 1012cm~ (-2) decreased to 2.5 * 1012cm~ (-2), and leakage current The density decreased from 1.1 * 10-3A/cm~2 to 3.2 * 10-6A/cm~2, saturation capacitance density increased from 1.36 F/cm~2 to 1.49 F/cm~2, and keep the electrical properties good stability; before HfO_2 film deposition, plasma surface treatment SiGe N_2/H2, N atoms to form Ge-N and Si-N bonds, reduced SiGe oxide and interface the fixed defect concentration, the leakage current density decreased from 2.4 * 10-4A/cm~2 to 4.6 * 10-6A/cm~2, saturation capacitance density increases from 1.53 F/cm~2 to 1.73 F/cm~2, the corresponding EOT decreased from 1.82nm to 1.64nm, 0.3MHz and C-V to 1MHz frequency dispersion curve decreased from 9.7% to 8.7%, reducing the interface state density (4 HfO_2/SiGe.) GHO films deposited on SiGe/Si substrates by using PEALD technology, the research of N_2 plasma by annealing GHO films on the GHO/SiGe layer stack structure chemical composition and electrical properties of the study found that Gd doping can. Hafnium based film formation inhibition of oxygen vacancy, reduce the generation of GHO/SiGe interface oxide, the HF based film composition more stoichiometric film improved saturation capacitance density, reducing the leakage current density; through the study found that N_2 plasma layer of GHO thin films by in situ annealing, oxygen vacancy N atoms occupy GHO the film, reducing the fixed defect density of GHO films, while N atoms with Ge-N and Si-N form passivation interface, reduce the interface oxide formation and interface state density, thin film leakage current density from 1.9 down to 2 * 108A/cm~2. * 10-5A/cm~2 (5) TiO_2-HfO_2 (THO) high k gate dielectric system applied to 16/14nm ETSOI CMOS process device, explored the THO high K films in small size (Lg=25nm) the feasibility of new structure devices. The study found that with THO as the gate dielectric thin films ETSOI MOSFET than with HfO_2 as the gate dielectric thin films ET SOIMOSFET has more excellent switching performance, short channel control and channel mobility. With THO as the gate dielectric films ETSOIpMOSFET device performance, on state current density of 4.63 x 1O-4A/ m, off state current density of 1.5 x 10-8A/ m, switch ratio is 3.1 * 104, cross guide a value of 2.67mA/V, DIBL 53mV/V, SS 65mV/dec, device hole mobility is 28cm~2V-1s-1; by using THO instead of HfO_2 as the gate dielectric film, can improve the overall performance of the device, the device to meet the demand. Further reduced

【學(xué)位授予單位】：北京有色金屬研究總院
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TN386;TB383.2

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本文編號：1440937