Title :
A Silicon-Embedded Transformer for High-Efficiency, High-Isolation, and Low-Frequency On-Chip Power Transfer
Author :
Rongxiang Wu ; Niteng Liao ; Xiangming Fang ; Sin, Johnny K. O.
Author_Institution :
State Key Lab. of Electron. Thin Films & Integrated Devices, Univ. of Electron. Sci. & Technol. of China, Chengdu, China
Abstract :
In this brief, a backside silicon-embedded transformer (BSET) with an improved isolation structure is proposed and demonstrated. The interleaved transformer coils are embedded inside a silicon substrate from the backside and connected to the front-side through vias. The isolation between the coils is achieved by the oxide layer between the Cu coil and the Si substrate, as well as the BCB (BenzoCycloButene) layer covering the backside of the transformer. The 2-mm2 BSET fabricated shows a best reported monolithic transformer efficiency of over 80% at a low frequency of 20 MHz. A 380 V isolation capability is achieved and shows the potential for various applications, such as USB (Universal Serial Bus) isolation. Only three masks are required for the fabrication. This technology is very suitable for on-chip isolated power transfer applications.
Keywords :
CMOS integrated circuits; coils; copper; embedded systems; integrated circuit interconnections; integrated circuit testing; monolithic integrated circuits; organic compounds; silicon; transformers; BCB layer; BSET; Cu; Si; USB isolation; backside silicon-embedded transformer; benzocyclobutene layer; frequency 20 MHz; interleaved transformer coils; isolation capability; monolithic transformer efficiency; on-chip isolated power transfer applications; oxide layer; silicon substrate; universal serial bus; voltage 380 V; Coils; Educational institutions; Fabrication; Power transformers; Silicon; Substrates; System-on-chip; Isolation technology; on-chip transformers; power transfer; through silicon via; through silicon via.;
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2014.2367502
