- 學位論文
超薄型(0.15微米)SOI LDMOS高壓(>800V)元件之研究
High Voltage (>800V) Power Device Study Based on Very Thin(0.15um) SOI LDMOS Technology
摘要
近年來，由於平面顯示器和通訊產品的推陳出新，伴隨著半導體產業的快速發展，使得功率元件的需求大幅增加。為了順應電路積體化的潮流，將功率元件與低壓電路整合在同一晶片上，傳統垂直式的元件結構必須改成橫向式的設計。而這之中最常使用的元件為 LDMOS元件， 如何製作一個省電低功率、高壓、快速的功率元件，將是一個重要的課題。 而我們使用了Tsuprem4 和Medici模擬軟體，模擬 LDMOSFET 元件的製程結構和電性模擬，以獲得最佳的製程參數。分析元件關閉和導通的特性，討論各種改進元件缺點的方法，將一些可行的技巧應用於BCD 製程，使元件可以被實際的製作和生產，並達到最佳化的設計。 本論文中利用線性參雜的原理模擬了N通道的LDMOSFET，並使用絕緣層上矽晶結構(SOI)，利用埋藏氧化層具有比矽更高的耐壓能力，本篇論文中在SOI絕緣層為2μm，且厚度為0.15μm的磊晶層(EPI)的製程。SOI LDMOS元件利用不同的N-drift 長度、不同Dose濃度及濃度梯度來改變其崩潰電壓(Breakdown Voltage)。 因此本論文最佳的元件結構及製程崩潰電壓最高可達到810V，而導通電阻(Ron)則可達126mΩ.cm2。
並列摘要
In recent years, because new display and communication products bring forth and substitutes the old ones, the demand for the power devices increases by a wide magnitude due to the rapid development of semiconductor industry. To follow the trend of circuits integration, power devices are integrated with low-voltage circuits on the same chip, and device designs are changed from tradition vertical structures to horizontal structures. As for the most used LDMOS devices, it will be an important subject how to make a power device with low power consumption, high voltage operation, and high speed. By using Tsuprem4 and Medici simulation software, the optimal manufacturing process parameters can be obtained by simulating the device structures and electrical properties of LDMOS devices. Based on researches including the electrical characteristics analysis of devices, the methods to improve device performances, and the compatible process technology applied to BCD devices, the design of devices can be achieved by optimized manufacture processes. By using the SOI technology with a buried oxide to stand high voltage and LDMOS devices of a linear doping N drift region to provide good electrical field distribution, SOI LDMOS with 2μm oxide and 0.15μm epi is studied in this thesis. The breakdown voltages of SOI LDMOS devices are thoroughly analyzed with the combinations of different N-drift lengths and different dose gradients. The devices with the optimization of device structures and processes can achieve a breakdown voltage of 810V, and on-state resistance of 126mΩ.cm2.