On-chip spiral inductor with novel gradually changed structure

✍ Scribed by Jing Liu; Yanling Shi; Xiuzhi Wen; Dawei Chen; Tian-Xing Luo; Hao Huang; Hongbo Ye; Yong Wang

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 434 KB
• Volume: 50
• Category: Article
• ISSN: 0895-2477
• DOI: 10.1002/mop.23611

✦ Synopsis

Abstract

On‐chip spiral inductors with sufficient quality factors are very important in many RF circuits. Based on the magnetic field intensity of a spiral inductor increasing gradually from outside to inside, this article presents a novel inductor structure with gradually changed metal width and space. Some design rules of this new structure have been obtained from a large number of data analyses. The sum of metal width and space of each coil is fixed while the ratio of the metal width to space is gradually reduced from outside to inside. Inductors have been fabricated and the obtained experimental results have verified the proposed design method. For a 7‐nH inductor on high‐resistivity silicon at 2.1 GHz, Q factor of 10 is 23.5% higher than the conventional inductor with fixed metal width and space, and is also 13.6% higher than the single gradually changed inductor with fixed space and gradually changed metal width. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2210–2213, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23611