12,590 research outputs found
Fabrication and characterisation of novel Ge MOSFETs
No full textAs high-k dielectrics are introduced into commercial Si CMOS (Complimentary Metal Oxide Semiconductor) microelectronics, the 40 year channel/dielectric partnership of Si/SiO2 is ended and the door opened for silicon to be replaced as the active channel material in MOSFETs (Metal Oxide Semiconductor Field Effect Transistor). Germanium is a good candidate as it has higher bulk carrier mobilities than silicon. In addition, Si and Ge form a thermodynamically stable SiGe alloy of any composition, allowing Ge to be implemented as a thin layer on the surface of a standard Si substrate. This thesis is a practical investigation on several aspects of Ge CMOS technology.
High-k dielectric Ge p-MOSFETs are electrically characterised. A large variation in interface state densities is demonstrated to be responsible for a threshold voltage shift and this is proportional to reciprocal peak mobility due to the Coulomb scattering of carriers by charged states. A theoretical mobility is fitted to that measured at 4.2 K and confirms that interface states are the main source of interface charged impurities.
The model demonstrates a reduction in the interface charged impurity density in p-MOSFETs that underwent a PMA (Post Metallisation Anneal) in hydrogen atmosphere and that the anneal also reduces the RMS (Root Mean Square) dielectric/semiconductor interface roughness, from an average of 0.60 nm to 0.48 nm.
High-k strained Ge p-MOSFETs are electrically characterised and have peak mobilities at 300 K (470 cm2 V-1 s-1) and 4.2 K (1780 cm2 V-1 s-1) far in excess of those measured for the unstrained Ge p-MOSFETs (285 cm2 V-1 s-1,785 cm2 V-1 s-1 respectively). Strained Ge n-MOSFETs perform significantly worse than standard Si P, - MOSFETs primarily due to a high source/drain resistance.
A 10 nm thick SiGe-01 (On Insulator) layer with a Ge composition of 58% is obtained from a 55 nm Si0_88Ge1o2. initial layer on 100 nm Si-Ol substrate via the germanium condensation technique. For the first time, germanium is demonstrated to diffuse through the BOX (Buried OXide) during Ge-condensation and into the underlying Si substrate. An order of magnitude increase in the calculated ITOX (Internal Thermal OXidation) rate of the BOX in the final stages of Ge-condensation is hypothesised to be responsible for stopping this diffusion
Electrodeposited Ni/Ge and germanide schottky barriers for nanoelectronics applications
No full textIn recent years metal/semiconductor Schottky barriers have found numerous applications in nanoelectronics. The work presented in this thesis focuses on the improvement of a few of the relevant devices using electrodeposition of metal on Ge for Schottky barrier fabrication. This low energy metallisation technique offers numerous advantages over the physical vapour deposition techniques. Electrical characteristics of the grown diodes show a high quality rectifying behaviour with extremely low leakage currents even on highly doped Ge. A non-Arrhenius behaviour of the temperature dependence is observed for the grown Ni/Ge diodes on lowly doped Ge that is explained by a spatial variation of the barrier heights. The inhomogeneity of the barrier hights is explained in line with an intrinsic surface states model for Ge. The understanding of the intrinsic surface states will help to create ohmic contacts for doped n-MOSFETs. NiGe were formed single phase by annealing. Results reveal that by using these high-quality germanide Schottky barriers as the source/drain, the subthreshold leakage currents of a Schottky barrier MOSFET could be minimised, in particular, due to the very low drain/body junction leakage current exhibited by the electrodeposited diodes. The Ni/Ge diodes on highly doped Ge show negative differential conductance at low temperature. This effect is attributed to the intervalley electron transfer in Ge conduction band to a low mobility valley. The results show experimentally that Schottky junctions could be used for hot electron injection in transferred-electron devices. A vertical Co/Ni/Si structure has been fabricated for spin injection and detection in Si. It is shown that the system functions electrically well although no magnetoresistance indicative of spin injection was observed
Observation of negative differential conductance in a reverse-biased Ni/Ge Schottky diode
No full textWe report the experimental observation of negative differential conductance in a Ni/Ge Schottky diode. With the aid of theoretical models and numerical simulation we show that, at reverse bias, electons tunnel into the high electric field of the depletion region. This scatters the electrons into the upper valley of the Ge conduction band, which has a lower mobility. The observed negative differential conductance is hence attributed to the transferred-electron effect. This shows that Schottky contacts can be used to create hot electrons for transferred-electron devices
Da he chang ge song "Wan yan shu" Li Jingquan
No full text珠江水利造反兵团.文字: 大合唱 歌颂《万言书》 李井泉;下款: 珠江水利造反兵团批判李井泉漫画 一九六七.三.六.裝裱後高寬: 129 x 39 cm.Zhujiang shui li zao fan bing tuan.Wen zi : Da he chang ge song "Wan yan shu" Li Jingquan; Xia kuan : Zhujiang shui li zao fan bing tuan pi pan Li Jingquan man hua 1967. 3. 6.Zhuang biao hou gao kuan : 129 x 39 cm
Qin Han yin sou
No full text王常編 ; 顧從德校.綫裝, 1函.框20.6x14.2公分, 8行, 每兩行按六分之一細分為上格下截, 上格内鈐印章, 下截為解說, 小字雙行每行20字. 朱絲欄, 紅格, 白口, 無魚尾, 四周單邊. 版心中鐫題名卷次, 下鐫葉次及"顧氏芸閣".刻書年據《引》.附原書底面夾板, 夾板上刻"秦漢印藪".Xian zhuang, 1 han.Kuang 20.6 x 14.2 gong fen, 8 hang, mei liang hang an liu fen zhi yi xi fen wei shang ge xia jie, shang ge nei qian yin zhang, xia jie wei jie shuo, xiao zi shuang hang mei hang 20 zi. Zhu si lan, hong ge, bai kou, wu yu wei, si zhou dan bian. Ban xin zhong juan ti ming juan ci, xia juan ye ci ji "Gu shi yun ge".Ke shu nian ju "yin".Fu yuan shu di mian jia ban, jia ban shang ke "Qin Han yin sou".Wang Chang bian ; Gu Congde jiao
Ge adatom adsorption, diffusion, and exchange on surfactant-covered Si(111) surfaces
No full textWe investigate the effects of various surfactants on the Ge adsorption, diffusion, and exchange on Si(111) surfaces through first-principles pseudopotential total-energy calculations. For surfactant-covered surfaces such as Si(111):Ga-1 x 1, Si(111):As-1 x 1,and Si(111):Sb-(root 3 x root 3)R30 degrees, Ge adatoms are generally incorporated into the surfactant layer. On the Ga-covered surface, we find-strong interactions between the Ge and Ga atoms, which result in large activation energies for both Ge surface diffusion and exchange with an underlying Ga atom. In the case of As surfactants, the activation energies for adatom diffusion and exchange are much reduced because of the weak couplings between the Ge and As atoms. Similarly, on the Sb-covered surface, the exchange between the adatoms and surfactants takes place easily; however, the surface diffusion is severely suppressed due to a relatively large energy gain by the exchange process. [S0163-1829(99)00128-9]
Xi yuan lu xiang yi: si juan, juan shou. v.1
No full text許槤編校.綫裝.框18.9x13.8公分, 分上下欄, 上欄註解18行14字, 下欄原文9行14字. 白口, 左右雙邊, 單黑魚尾. 版心上鐫題名, 中鐫卷次, 小題, 下鐫葉次. 眉端刻評.書名頁署"洗冤錄詳義, 光緖丙子秋九月泉唐葛氏嘯園開雕, 上虞徐三庚署".前有光緖二年[1876]葛元煦序, 言重刻此書事.卷四末刻"嘯園藏板", "上海新北門內謝潤卿鐫字"With: 洗冤錄摭遺 : 二卷 / 葛元煦.鈐"承業堂藏書印", "長□彭氏", "莊兆祥印"Xian zhuang.Kuang 18.9 x 13.8 gong fen, fen shang xia lan, shang lan zhu jie 18 hang 14 zi, xia lan yuan wen 9 hang 14 zi. Bai kou, zuo you shuang bian, dan hei yu wei. Ban xin shang juan ti ming, zhong juan juan ci, xiao ti, xia juan ye ci. Mei duan ke ping.Detailed notes in vernacular field only.Detailed notes in vernacular field only.Detailed notes in vernacular field only.Xu Lian bian jiao.With: Xi yuan lu zhi yi : er juan / Ge Yuanxu.Qian "Cheng ye tang cang shu yin", "Chang [...] Peng shi", "Zhuang Zhaoxiang yin
Han yu chang yong 100 ci yuan liu yan bian yan jiu
No full textBen shu yi xian dai han yu shi yong pin lü zui gao de 100 ge dan yin ci he 20 ge fu yin ci wei yan jiu dui xiang,Zhu yi jie shao qi xian dai chang jian yong fa,Shang su yuan,Xia tan liu,Gou le chu zhei 120 ge chang yong ci de li shi fa zhan yan bian gui j
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