# Accuracy considerations for dielectric measurements of semiconductor wafers using free space microwave measurement system in 8-13 GHz range

05 Oct 2004-pp 177-181

TL;DR: An algorithm using only transmission measurements to calculate the complex permittivity of p-type and n-type silicon semiconductor wafers using a spot-focused free-space measurement system was developed in this article.

Abstract: An algorithm using only transmission measurements to calculate the complex permittivity of p-type and n-type silicon semiconductor wafers using a spot-focused free-space measurement system was developed The dielectric constant obtained was close to published values for silicon wafers The errors associated with the measurement of the complex permittivity values are discussed, and comparisons between the measured and calculated magnitude and phase of the forward reflection and transmission coefficients are presented In this method, the free-space reflection and transmission coefficients, S/sub 11/ and S/sub 21/, are measured for a silicon wafer sandwiched between two teflon plates which are quarter-wavelength at midband The actual reflection and transmission coefficient, S/sub 11/ and S/sub 21/ of the silicon wafers are then calculated from the measured S/sub 11/ and S/sub 21/ by using ABCD matrix transformation in which the complex permittivity and thickness of the teflon plates are known Results are reported in the frequency range of 8-125 GHz

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TL;DR: In this article, a free space, non-destructive method for measuring the complex permittivity of a double-layer bulk dielectrics and thin fllm oxide layers at microwave frequencies has been developed.

Abstract: A free-space, non-destructive method for measuring the complex permittivity of a double-layer bulk dielectrics and thin fllm oxide layers at microwave frequencies have been developed. The method utilizes a spot-focusing antenna system in conjunction with a vector network analyzer in the range of 18{26GHz. The bulk dielectric was measured using the Transmission Method and Metal-Backed Method, while the Metal-Backed Method was used to investigate the thin fllms. Both types of samples were sandwiched between two quarter-wavelength Te∞on plates to improve the mismatch at the frequencies of measurement. The thin fllm sample arrangement was backed by an additional metal plate. The double-layer bulk dielectric samples were Te∞on-PVC and Plexiglas-PVC, while the thin fllm samples consisted of SiO2 layers of difierent thicknesses grown on doped and undoped Si wafer substrates. The relative permittivity obtained for PVC ranged between 2.62 to 2.93, while those for Plexiglas exhibited values between 2.45 to 2.63. The relative permittivity of SiO2 deposited on these wafers was between 3.5 to 4.5. All these values are in good agreement with published data. The advantage of the method is its ability to measure the dielectric properties of the fllms at the mid- frequency band irrespective of the substrate type used. Simulations of the measurement setup were carried out using CST Microwave Studio and the simulation results agreed closely with the measurements.

34 citations

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01 Dec 2010TL;DR: In this article, two methods for the calculation of complex permittivity of double-layer dielectric materials measured by a spot-focusing free-space measurement system have been developed.

Abstract: Two methods for the calculation of complex permittivity of double-layer dielectric materials measured by a spot-focusing free-space measurement system have been developed. Standard materials have been used to test these methods and further works will be carried out on SiO 2 wafer. The dielectric constants obtained were close to the published values. The two methods developed are Transmission Method and Metal-Backed Method. The S 11 , S 21 , and S 22 are measured for Transmission Method, while only S 11 is measured for Metal-Backed Method. In both methods, the samples are sandwiched between two Teflon plates which are quarter wavelength at mid-band frequency. Results are reported in the frequency range of 18–26GHz.

10 citations

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01 Dec 2008TL;DR: A microwave non-destructive testing (MNDT) method to determine the ripeness of Siamese mangoes at a frequency range of 18 to 26.5 GHz (K-Band) using free space microwave measurement (FSMM) system is presented in this article.

Abstract: This project presents a microwave non-destructive testing (MNDT) method to determine the ripeness of Siamese mangoes at a frequency range of 18 to 26.5 GHz (K-Band) using free space microwave measurement (FSMM) system. The basic components of the FSMM system are spot focusing horn lens antennas, a vector network analyzer (VNA) and a computer. In this method, the free space reflection, S11 and transmission, S21 coefficients are measured for the samples sandwiched between two Teflon plates that are quarter wavelengths at mid-band. The thru, reflect and line (TRL) calibration technique is used to eliminate the effect of undesirable multiple reflections. The extracted S11 and S21 are keyed in a developed algorithm to calculate the complex permittivity of moisture contents within the samples. Results have shown that the dielectric constants for ripe and unripe mangoes are between 26.3 to 29.5 and 26.1 to 29.2 respectively. Other parameters including loss factor and loss tangent are also discussed.

4 citations

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01 Dec 2007

TL;DR: In this article, the authors describe the 3D simulation and measurements of free space characterization for the complex permittivity of p-type and n-type doped silicon wafers at K-band.

Abstract: This paper describes the 3D simulation and measurements of free space characterization for the complex permittivity of p-type and n-type doped silicon wafers at K-band. The component of this free space measurement system (FSMM) consists of Millitech series GOA Gaussian optics lens antennas, vector network analyzer (VNA) and a high performance workstation. The antennas were modeled and simulated using Computer Simulation Technology (CST) software. The thru, reflect and line (TRL) calibration technique were used to eliminate the effect of undesirable multiple reflections. The simulation and measurement results are presented where good agreements are observed.

3 citations

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TL;DR: In this article, a free-space measurement system operating in the 8.2-40 GHz frequency range is used to measure the reflection and transmission coefficients, S/sub 11/ and S/ sub 21/, of planar samples.

Abstract: A free-space measurement system operating in the 8.2-40-GHz frequency range is used to measure the reflection and transmission coefficients, S/sub 11/ and S/sub 21/, of planar samples. The complex electric permittivity and the magnetic permeability are calculated from the measured values of S/sub 11/ and S/sub 21/. The measurement system consists of transmit and receive horn lens antennas, a network analyzer, mode transitions, and a computer. Diffraction effects at the edges of the sample are minimized by using spot-focusing lens antennas. Errors due to multiple reflections between antennas via the surface of the sample are corrected by using a free-space TRL (thru, reflect, line) calibration technique. For thin, flexible samples, the sample had to be sandwiched between two half-wavelength (at mid-band) quartz plates to eliminate sagging. Results are reported in the frequency range of 8.6-13.4 GHz for materials such as Teflon, sodium borosilicate glass, and microwave-absorbing materials. >

743 citations

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TL;DR: A free space microwave measurement system that is used for the high-temperature measurement of dielectric constants and loss tangents of homogeneous materials and that is applicable to composite materials as well is discussed in this paper.

Abstract: A free-space microwave measurement system that is used for the high-temperature measurement of dielectric constants and loss tangents of homogeneous materials and that is applicable to composite materials as well is discussed. The system is capable of operating in the 5.85-40-GHz frequency range and ambient to 850 degrees C temperature range. A computer is used to control and coordinate furnace temperature, network analyzer functions, and data storage. Dielectric constants and loss tangents of the materials are calculated from the measured values of S/sub 21/. The measurement system, including the high-temperature furnace and the calibration technique, is described. Dielectric constants and loss tangents are presented for fused quartz and boron nitride grade HP in the frequency range 13.0-17.4 GHz and the temperature range from ambient to 850 degrees C. >

137 citations

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TL;DR: In this article, the complex microwave conductivity of lightly-doped n and p-type silicon and genmanium was measured by observing the reflectivity of the circular T E01 mode at 48 GHz and were thus free of errors caused by the impedance of the waveguide.

Abstract: This paper presents measurements of the complex microwave conductivity of lightly‐doped n‐ and p‐type silicon and genmanium as functions of impurity concentration and of temperature between 77° and 300°K. The measurements were obtained by observing the reflectivity of the circular T E01 mode at 48 GHz and are thus free of errors caused by the impedance of the waveguide‐sample contact. Analysis utilized currently accepted scattering models including ionized impurity scattering, intravalley acoustic and optical mode scattering, and intervalley scattering. The results are used to investigate the temperature and doping dependence of the average relaxation time and the conductivity ``effective'' mass.

47 citations

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TL;DR: The utility of a quarter-wave transformer for precise measurement of complex microwave conductivity of semiconductors has been demonstrated in this paper, where it has been shown that the improvement in measurement accuracy is nearly by a factor of 3 over the conventional reflection measurement using a Teflon transformer.

Abstract: The utility of a quarter-wave transformer for precise measurement of complex microwave conductivity of semiconductors has been demonstrated. It has been shown for a chosen conductivity of 9 /spl Omega//spl dot/cm that the improvement in measurement accuracy is nearly by a factor of 3 over the conventional reflection measurement using a Teflon transformer.

5 citations

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01 Jul 2004TL;DR: In this paper, a contactless and non-destructive method is presented to characterize p-type and n-type silicon semiconductor wafers using a spot-focused free-space measurement system.

Abstract: A contactless and non-destructive method is presented to characterize p-type and n-type silicon semiconductor wafers using a spot-focused free-space measurement system. In this method, the free-space reflection and transmission coefficients, S 11 and S 21 , are measured for silicon wafer sandwiched between two teflon plates which are quarter-wavelength at mid-band. The actual reflection and transmission coefficient, S 11 and S 21 of the silicon wafers are then calculated from the measured S 11 and S 21 by using ABCD matrix transformation in which the complex permittivity and thickness of the teflon plates are known. Complex permittivity are computed using only the transmission coefficient, S 21 . From the complex permittivity, the resistivity and conductivity can be obtained. Results are reported in the frequency range of 9–12.5 GHz. The dielectric constant obtained were close to published values for silicon wafers and the resistivities agree well with that measured by other conventional method.

4 citations