B. Rejaei | Sharif University of Technology (original) (raw)
Papers by B. Rejaei
A series of microstrips with patterned Ni 78 Fe 22 ferromagnetic cores have been investigated for... more A series of microstrips with patterned Ni 78 Fe 22 ferromagnetic cores have been investigated for RF applications. The devices have been integrated onto a silicon substrate by using a fully IC-compatible process. The Ni 78 Fe 22 films were deposited by electroplating onto Si at room temperature and were structured into rectangular prisms with large aspect ratios, i.e., 10 : 1 and 40 : 1. Measurements have been performed using a network analyzer. Voltage attenuation of 19 dB/cm has been obtained at 3.9 GHz on a 2-mm-long strip line. The propagating wavelength is reduced by 60% compared to a control device without ferromagnetic core.
This paper addresses a reduction in loss in silicon substrates through reduced-thickness conducto... more This paper addresses a reduction in loss in silicon substrates through reduced-thickness conductor-backed substrates. Specific results obtained include characteristics in inductor quality and isolation between inductors through a reduced substrate thickness. Dependence of eddy-current degradation (from electromagnetic simulation results) of spiral-inductor characteristics on the distance of the backside conductor from the coil are documented. Finally, characterization of a conventional microstrip line over a non-uniform substrate is done to understand its degradation in dependence of the non-uniform substrate.
30th European Solid-State Device Research Conference, 2000
We present an experimental study of the effect of the accumulation or inversion layer at the surf... more We present an experimental study of the effect of the accumulation or inversion layer at the surface of a high-resistivity silicon substrate on the loss of transmission lines. It is shown that the relative contribution of the surface channel to the total loss becomes increasingly significant as the silicon resistivity decreases. The experiments demonstrate that the effect of the surface channel on the loss of an integrated microstrip is considerably lower than that of a comparable coplanar waveguide, favoring microstrips for integration on high-resistivity silicon substrates.
This paper addresses the properties of a surface-pas- sivated (enhanced) high-resistivity silicon... more This paper addresses the properties of a surface-pas- sivated (enhanced) high-resistivity silicon (HRS) substrate for use in monolithic microwave technology. The detrimental effects of conductive surface channels and their variations across the wafer related to the local oxide and silicon/silicon-dioxide interface quality are eliminated through the formation of a thin amorphous layer at the wafer surface. Without passivation, it is found that the surface channels greatly degrade the quality of passive compo- nents in HRS by masking the excellent properties of the bulk HRS substrate and by causing a spread in parameters and peak values across the wafer. Moreover, it is seen that the surface passivation leads to excellent agreement of the characteristics of fabricated components and circuits with those predicted by electromagnetic (EM) simulation based on the bulk HRS properties. This is ex- perimentally verified for lumped (inductors and transformers) and distributed (coplanar wavegu...
2003 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 2003. Digest of Papers., 2003
Proceedings of the Bipolar/BiCMOS Circuits and Technology Meeting, 2002
Add-on process modules as enhancements of standard high-frequency silicon integration processes a... more Add-on process modules as enhancements of standard high-frequency silicon integration processes are discussed. Such modules can be added without any interference with the core process before (pre-process modules), during (mid-process modules), or after (post-process modules) the circuit integration. Most of those modules have the purpose to overcome shortcomings of silicon as a microwave substrate.
2001 IEEE MTT-S International Microwave Sympsoium Digest (Cat. No.01CH37157), 2001
ABSTRACT This paper describes a high-speed measurement protocol using a high-order implementation... more ABSTRACT This paper describes a high-speed measurement protocol using a high-order implementation of the complex power series representation (CPSR). The CPSR is used to relate AM-AM and AM-PM conversion (large signal S21) to the 3rd-order intermodulation distortion (IM3) of an amplifier up to gain compression. This method requires the use of a network analyzer only and eliminates the need for a spectrum analyzer speeding-up the measurements tremendously. The method has proven to be very powerful in a real-time optimization of bias parameter of a novel linear distributed amplifier for base stations
2000 Topical Meetings on Silicon Monolithic Integrated Circuits in RF Systems. Digest of Papers (Cat. No.00EX397), 2000
2000 Topical Meetings on Silicon Monolithic Integrated Circuits in RF Systems. Digest of Papers (Cat. No.00EX397), 2000
2001 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems. Digest of Papers (IEEE Cat. No.01EX496), 2001
The maximum available gain is used to evaluate the quality of transformers similarly to that of a... more The maximum available gain is used to evaluate the quality of transformers similarly to that of active devices. A highly structured patterned ground shield is shown to improve the frequency response of the maximum available gain of a transformer at high frequencies
Digest of Papers. 2005 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 2005., 2005
An optimized Saddle-add-on metallization process is used on surface passivated high resistivity s... more An optimized Saddle-add-on metallization process is used on surface passivated high resistivity silicon substrate to implement very high quality (Q) factor inductors. Test inductors with 5 and 10 nH inductance values are realized and measured to have maximum Q values of 37 at 1.5 GHz and 32 at 900 MHz respectively.
Physica B: Condensed Matter, 1996
ABSTRACT
Transactions of the Magnetics Society of Japan, 2002
Digest. International Electron Devices Meeting,, 2002
Integrated solenoidal radio-frequency (RF) inductors and transformers with a ferromagnetic core a... more Integrated solenoidal radio-frequency (RF) inductors and transformers with a ferromagnetic core are demonstrated by using a fully IC-compatible fabrication process. For a 500-nmthick Ni 80 Fe 20 film, a cut-off frequency of over 7.5 GHz for a 2.5-nH inductor is realized. Optimum inductor design based on tailored inductance, quality factor, and cut-off frequency is discussed. RF transformers realized have a coupling factor of ~ 70% up to 200 MHz.
Digest. International Electron Devices Meeting,, 2002
A cost-effective add-on process module is proposed for reduction of ohmic losses of RF inductors ... more A cost-effective add-on process module is proposed for reduction of ohmic losses of RF inductors and interconnects in RF/BiCMOS and RF/CMOS technologies built on logic CMOS processes. The module is based on the local thickening of the top metal layer of the thin CMOS interconnects by Cu plating. A record quality factor of 13 is achieved for a 10-nH inductor on a conventional 5-Ω-cm silicon substrate.
Synthetic Metals, 1997
ABSTRACT
Solid-State Electronics, 2007
Integrated radio-frequency solenoids with micro-patterned magnetic cores for reduced dimensions a... more Integrated radio-frequency solenoids with micro-patterned magnetic cores for reduced dimensions and compatibility with CMOS/ BiCMOS process technology are presented and discussed. It is demonstrated that the use of a ferromagnetic (FM) core leads to a more than 20-fold enhanced inductance per area. This is achieved by tailoring the anisotropy of the FM core and the design of the metal coil structure. Both a higher operating frequency and a larger inductance are obtained by increasing the shape aspect ratio of the FM core and by depositing the magnetic film under an external magnetic field. A reference to an optimum shape anisotropy has been created by measuring the FM core inductors with an external DC magnetic field. An optimum practical trade-off of inductance and operating frequency results from patterning of the FM core.
Proceedings of the 2000 BIPOLAR/BiCMOS Circuits and Technology Meeting (Cat. No.00CH37124), 2000
2011 IEEE 11th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 2011
An integrated waveguide realized on (high resistivity) silicon using an IC-compatible process is ... more An integrated waveguide realized on (high resistivity) silicon using an IC-compatible process is reported in this work. The manufacturing process flow is based on substrate transfer technique and KOH etching, giving the resulting waveguide a trapezoidal cross-section. For this structure, the analysis of the propagating modes described here shows that it is possible to define a TE10-like mode, whose field
The aim of this work is to provide a tool for the design of optimised inductors. It is based on a... more The aim of this work is to provide a tool for the design of optimised inductors. It is based on a compact model, where the physical behaviour is described through analytical expressions, rather than numerical computations or fitted expressions. The inductance value and the maximum disposable are the required input data. The output is directly the layout of the optimised inductor and the frequency dependent model. The tool has been applied to the design of a 2.4 GHz integrated differential VCO. An improvement of 4 dBc/Hz @ 100KHz in the phase noise might be obtained.
A series of microstrips with patterned Ni 78 Fe 22 ferromagnetic cores have been investigated for... more A series of microstrips with patterned Ni 78 Fe 22 ferromagnetic cores have been investigated for RF applications. The devices have been integrated onto a silicon substrate by using a fully IC-compatible process. The Ni 78 Fe 22 films were deposited by electroplating onto Si at room temperature and were structured into rectangular prisms with large aspect ratios, i.e., 10 : 1 and 40 : 1. Measurements have been performed using a network analyzer. Voltage attenuation of 19 dB/cm has been obtained at 3.9 GHz on a 2-mm-long strip line. The propagating wavelength is reduced by 60% compared to a control device without ferromagnetic core.
This paper addresses a reduction in loss in silicon substrates through reduced-thickness conducto... more This paper addresses a reduction in loss in silicon substrates through reduced-thickness conductor-backed substrates. Specific results obtained include characteristics in inductor quality and isolation between inductors through a reduced substrate thickness. Dependence of eddy-current degradation (from electromagnetic simulation results) of spiral-inductor characteristics on the distance of the backside conductor from the coil are documented. Finally, characterization of a conventional microstrip line over a non-uniform substrate is done to understand its degradation in dependence of the non-uniform substrate.
30th European Solid-State Device Research Conference, 2000
We present an experimental study of the effect of the accumulation or inversion layer at the surf... more We present an experimental study of the effect of the accumulation or inversion layer at the surface of a high-resistivity silicon substrate on the loss of transmission lines. It is shown that the relative contribution of the surface channel to the total loss becomes increasingly significant as the silicon resistivity decreases. The experiments demonstrate that the effect of the surface channel on the loss of an integrated microstrip is considerably lower than that of a comparable coplanar waveguide, favoring microstrips for integration on high-resistivity silicon substrates.
This paper addresses the properties of a surface-pas- sivated (enhanced) high-resistivity silicon... more This paper addresses the properties of a surface-pas- sivated (enhanced) high-resistivity silicon (HRS) substrate for use in monolithic microwave technology. The detrimental effects of conductive surface channels and their variations across the wafer related to the local oxide and silicon/silicon-dioxide interface quality are eliminated through the formation of a thin amorphous layer at the wafer surface. Without passivation, it is found that the surface channels greatly degrade the quality of passive compo- nents in HRS by masking the excellent properties of the bulk HRS substrate and by causing a spread in parameters and peak values across the wafer. Moreover, it is seen that the surface passivation leads to excellent agreement of the characteristics of fabricated components and circuits with those predicted by electromagnetic (EM) simulation based on the bulk HRS properties. This is ex- perimentally verified for lumped (inductors and transformers) and distributed (coplanar wavegu...
2003 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 2003. Digest of Papers., 2003
Proceedings of the Bipolar/BiCMOS Circuits and Technology Meeting, 2002
Add-on process modules as enhancements of standard high-frequency silicon integration processes a... more Add-on process modules as enhancements of standard high-frequency silicon integration processes are discussed. Such modules can be added without any interference with the core process before (pre-process modules), during (mid-process modules), or after (post-process modules) the circuit integration. Most of those modules have the purpose to overcome shortcomings of silicon as a microwave substrate.
2001 IEEE MTT-S International Microwave Sympsoium Digest (Cat. No.01CH37157), 2001
ABSTRACT This paper describes a high-speed measurement protocol using a high-order implementation... more ABSTRACT This paper describes a high-speed measurement protocol using a high-order implementation of the complex power series representation (CPSR). The CPSR is used to relate AM-AM and AM-PM conversion (large signal S21) to the 3rd-order intermodulation distortion (IM3) of an amplifier up to gain compression. This method requires the use of a network analyzer only and eliminates the need for a spectrum analyzer speeding-up the measurements tremendously. The method has proven to be very powerful in a real-time optimization of bias parameter of a novel linear distributed amplifier for base stations
2000 Topical Meetings on Silicon Monolithic Integrated Circuits in RF Systems. Digest of Papers (Cat. No.00EX397), 2000
2000 Topical Meetings on Silicon Monolithic Integrated Circuits in RF Systems. Digest of Papers (Cat. No.00EX397), 2000
2001 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems. Digest of Papers (IEEE Cat. No.01EX496), 2001
The maximum available gain is used to evaluate the quality of transformers similarly to that of a... more The maximum available gain is used to evaluate the quality of transformers similarly to that of active devices. A highly structured patterned ground shield is shown to improve the frequency response of the maximum available gain of a transformer at high frequencies
Digest of Papers. 2005 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 2005., 2005
An optimized Saddle-add-on metallization process is used on surface passivated high resistivity s... more An optimized Saddle-add-on metallization process is used on surface passivated high resistivity silicon substrate to implement very high quality (Q) factor inductors. Test inductors with 5 and 10 nH inductance values are realized and measured to have maximum Q values of 37 at 1.5 GHz and 32 at 900 MHz respectively.
Physica B: Condensed Matter, 1996
ABSTRACT
Transactions of the Magnetics Society of Japan, 2002
Digest. International Electron Devices Meeting,, 2002
Integrated solenoidal radio-frequency (RF) inductors and transformers with a ferromagnetic core a... more Integrated solenoidal radio-frequency (RF) inductors and transformers with a ferromagnetic core are demonstrated by using a fully IC-compatible fabrication process. For a 500-nmthick Ni 80 Fe 20 film, a cut-off frequency of over 7.5 GHz for a 2.5-nH inductor is realized. Optimum inductor design based on tailored inductance, quality factor, and cut-off frequency is discussed. RF transformers realized have a coupling factor of ~ 70% up to 200 MHz.
Digest. International Electron Devices Meeting,, 2002
A cost-effective add-on process module is proposed for reduction of ohmic losses of RF inductors ... more A cost-effective add-on process module is proposed for reduction of ohmic losses of RF inductors and interconnects in RF/BiCMOS and RF/CMOS technologies built on logic CMOS processes. The module is based on the local thickening of the top metal layer of the thin CMOS interconnects by Cu plating. A record quality factor of 13 is achieved for a 10-nH inductor on a conventional 5-Ω-cm silicon substrate.
Synthetic Metals, 1997
ABSTRACT
Solid-State Electronics, 2007
Integrated radio-frequency solenoids with micro-patterned magnetic cores for reduced dimensions a... more Integrated radio-frequency solenoids with micro-patterned magnetic cores for reduced dimensions and compatibility with CMOS/ BiCMOS process technology are presented and discussed. It is demonstrated that the use of a ferromagnetic (FM) core leads to a more than 20-fold enhanced inductance per area. This is achieved by tailoring the anisotropy of the FM core and the design of the metal coil structure. Both a higher operating frequency and a larger inductance are obtained by increasing the shape aspect ratio of the FM core and by depositing the magnetic film under an external magnetic field. A reference to an optimum shape anisotropy has been created by measuring the FM core inductors with an external DC magnetic field. An optimum practical trade-off of inductance and operating frequency results from patterning of the FM core.
Proceedings of the 2000 BIPOLAR/BiCMOS Circuits and Technology Meeting (Cat. No.00CH37124), 2000
2011 IEEE 11th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 2011
An integrated waveguide realized on (high resistivity) silicon using an IC-compatible process is ... more An integrated waveguide realized on (high resistivity) silicon using an IC-compatible process is reported in this work. The manufacturing process flow is based on substrate transfer technique and KOH etching, giving the resulting waveguide a trapezoidal cross-section. For this structure, the analysis of the propagating modes described here shows that it is possible to define a TE10-like mode, whose field
The aim of this work is to provide a tool for the design of optimised inductors. It is based on a... more The aim of this work is to provide a tool for the design of optimised inductors. It is based on a compact model, where the physical behaviour is described through analytical expressions, rather than numerical computations or fitted expressions. The inductance value and the maximum disposable are the required input data. The output is directly the layout of the optimised inductor and the frequency dependent model. The tool has been applied to the design of a 2.4 GHz integrated differential VCO. An improvement of 4 dBc/Hz @ 100KHz in the phase noise might be obtained.