African Physical Review (2008) 2 Special Issue (Microelectronics): 0048 98
Design and Optimisation of Circular and Inductors for Silicon-based RFIC Application
A. Ziouche and M. T. Belaroussi
Division Microélectronique et Nanotechnologie, Centre de Développement des Technologies Avancées, Baba Hassen, Alger, Algeria
1. Introduction
In this paper, spiral inductors for RF application, which are designed on a silicon substrate by using standards 0.35 µ m CMOS technology, are described. Analyzed and designed with ASITIC (a tool from the University of Berkeley), which accurately takes into account the parasitic effects.
This study shows the possibility of obtaining an optimal inductance having a high quality factor of 15. This result is carried out without resorting to the specific processes such as the digging of the substrate under the inductors or the use of a thick layer in gold. The use of circular form, with optimization of geometrical parameters like spacing between two adjacent turn, the track width and the number of turns, can ensure high quality factors.
2. Results
Fig.1: Design of circular inductor 2-turn, 2µm spacing and width 45µm.
a) Effects of metal conductor width
1 2 3 4 5 6 7
2,0 2,5 3,0 3,5 4,0 4,5
28µm 26µm 24µm 22µm 20µm 19µm 18µm 17µm
Resistanse serie Rs (ohm)
frequence(GHZ)
16µm
Fig.2: Inductance versus frequency for 2-turn and 2µm spacing with width varying from 16µm to 28µm.
1 2 3 4 5 6
2 4 6 8 10 12 14 16
16µm 17µm 18µm 19µm 20µm 22µm 24µm
le facteur de qualité
frequence(GHZ)
Fig.3: Quality factor versus frequency for 2-turn and 2µm spacing with width varying from 16µm to 28µm.
African Physical Review (2008) 2 Special Issue (Microelectronics): 0048 99
b) Effects of metal conductor-to conductor spacing
0 1 2 3 4 5 6 7 8 9 10 11
6,0 6,5 7,0 7,5 8,0 8,5 9,0 6 7 8 9 10 11
carrée
freq. résonance (GHz)
Espacement S(µm) carrée
circulaire
Facteur de qualité Q
circulaire
Fig.4: Quality factor and frequency of resonance for 3- turn and 25µm width with spacing varying from 0.5µm to 10µm.
c) Effects of number of turns
0 2 4 6 8 10
1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0
N=2,5 N=3 N=3,5
frequence(GHZ)
inductance Ls(nH)
N=4
Fig.5: Inductance versus frequency for 25µm width and 2µm spacing with number of turn varying from 1 to 4.
1 2 3 4 5 6 7
-2 0 2 4 6 8 10 12 14 16 18 20
N=4 N=3,5
N=3
facteur de qualité Q
frequence(GHz)
N=2,5
Fig.6: Quality factor versus frequency for 25µm width and 2µm spacing with number of turn varying from 1 to 4.
