Study of electron transportation in SOI and Poly-Silicon Point-Junction Nanostructures

• Main Authors: Weng Wen-Ching, 翁文慶
• Other Authors: Wan Yue-Min
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/99327281733451255121

碩士 === 義守大學 === 電子工程學系 === 91 === Single Electron Transistor is the important device in nanostructure semiconductor. Its operation is based on the Coulomb interaction and quantum confinement of the electronics charge to produce the single electron tunneling phenomena of nanostructure. The feature, electron transport in the SET devices one by one, is different from FET in which there are uncountable electrons transporting. Furthermore, due to the characteristics of small size and low power consumption of a SET transistor, it may be a promising candidate to be a new potential device. In many cases, it could replace the FET, such as high-density memory. First of all, we will introduce the single electron theory－Orthodox theory and its special properties including Coulomb Blockade, Conductance Oscillation and Coulomb Staircase, then to fabricate the device. Among the processes, lithography is the key point. We use two newly techniques－E-Beam Lithography（EBL）and Proximity Effectcorrection to fabricate the device. Due to the SET structure must be ultra small to observe the charging effect, so we fabricate the device by Leica WEPRINT 200 E-Beam Lithography system. For improving the resolution, we study the lithography condition, include the dosage of electron beam（about 10~12 µC/cm2）, the choice of photoresist（NEB22A or DSE, the thickness of photoresist）and Proximity effect. With careful design, we can define ultra small pattern on SOI wafer. In this letter we utilize Proximity Effectcorrection technology and RTO to define the charge island with tunneling junction, and to observe the Si-SET Coulomb Oscillation. In order to reduce thermal tunneling, we measure our sample in He dilution refrigerator system. Dilution refrigerator can provide a low-temperature environment（below 40 K）. Due to the ultra small signal of nano device, we need to care of environment noise. Thus good shielding is necessary in order to avoid unwanted tunneling event to promote our system accuracy.