Showing papers on "Van der Pauw method published in 1975"
TL;DR: In this article, the authors measured the surface concentration of free electrons as a function of ion dose reached a maximum of approximately 1013 electron/cm2 with an average Hall mobility of 2000 cm2/V sec.
Abstract: GaAs has been doped by the ion implantation of silicon, sulphur, selenium and tin. After annealing at 700°C, the layers were n-type in all cases but with the heavier ions, selenium and tin, it was necessary to implant above room temperature. Van der Pauw measurements showed that for all the impurities the surface concentration of free electrons as a function of ion dose reached a maximum of approximately 1013 electron/cm2 with an average Hall mobility of 2000 cm2/V sec. The spatial distributions of active donors were obtained from both differential Hall measurements and capacitance measurements on reverse biased Schottky barriers. The maximum carrier density measured was 1018/cm3 at the peak of the distribution of tin ions implanted at 200°C. With selenium and tin implants the concentration and mobility of free electrons and the depth of the donor distribution were dose dependent. The cathodoluminescence spectra from implanted layers were dominated by broad low energy bands due to recombination at defects. A VGa-Si complex was thought to be responsible for one of the most intense bands at 1·18 eV. The results indicate that under certain conditions both defects and impurities migrate into the substrate.
39 citations
TL;DR: In this article, the temperature dependence of the Hall coefficient RH and conductivity sigma of n-InSb in the range 77-300K has been determined using the Van der Pauw technique.
Abstract: The temperature dependence of the Hall coefficient RH, and conductivity sigma of n-InSb in the range 77-300K has been determined using the Van der Pauw technique. The experimental values of the Hall mobility are analysed in the relaxation time approximation for both the parabolic and non-parabolic cases, considering electron scattering by ionized impurities, polar optical phonons and acoustic deformation potential. The influence of electron-electron scattering on polar optical and ionized impurities has also been studied.
12 citations
TL;DR: In this paper, the Schottky gate on a van der Pauw cloverleaf is modulated by an a.c. signal and a. c. signal is synchronously detected.
Abstract: Depletion type profiling methods offer clear advantages over stripping techniques provided that depletion of the region of interest can be attained without the surface field exceeding the critical value for the material under test. Two well known methods are (i) differential CV measurements by which n(x) may be determined with a high degree of accuracy, and (ii) stepwise depletion from a Schottky or MOS gate suitably located in a sample in Hall geometry by which n(x) and mu (x) can be measured less accurately. The author outlines a method combining virtues of both approaches in which the stepped d.c. applied to the Schottky gate on a van der Pauw cloverleaf is modulated by an a.c. signal and a.c. components of Hall and van der Pauw voltages are synchronously detected. Equations governing the extraction of mu (x) and n(x) from the data are given and two sample experimental results presented.
10 citations
TL;DR: In this article, the van der Pauw method was used to measure the resistivity, carrier concentration and Hall mobility of poly Si layers by using a simplified model of the poly Si-oxide-single crystal silicon structure.
Abstract: The resistivity, carrier concentration and Hall mobility of the boron diffused poly Si layers were measured by using the van der Pauw method. The effects of the thickness and deposition temperature of the poly Si layers and of the boron diffusion temperature and time on these electrical characteristics were investigated. The desirable boron diffusion condition for silicon gate MOS devices is 30 min at 950°C. With this condition, the resistivity of 1·2 × 10−3 Ω cm was obtained. The Hall mobility increases with the thickness and the deposition temperature of the poly Si layers due to the increase of the grain size and takes the maximum value of 30 cm2.V−1.sec−1 in the experimental range. The relationship between the boron diffusion and carrier concentration has been analyzed by using a simplified model of the poly Si-oxide-single crystal silicon structure. The carrier concentration increases with a dimensionless variable 1 L p (= D p t l p 2 ) and saturates to be about 40 per cent of the solid solubility limit of boron in single crystal silicon substrates due to the precipitation of boron at the grain boundaries.
9 citations
TL;DR: In this paper, the experimental curves of conductivity and Hall coefficient as a function of pressure have been fitted to a two conduction band model with various band parameters taken as adjustable.
Abstract: Homogeneous polycrystalline n type samples of the alloys Ga(AsxSb1−x) and (GaxIn1−x)Sb have been prepared from a stoichiometric melt by directional freezing methods. Room temperature measurements of electrical conductivity and Hall coefficient as a function of hydrostatic pressure up to 12 kbars have been made on samples of different composition by means of the van der Pauw technique, all specimens used in the measurements being carefully selected to avoid the presence of grain boundary effects. The experimental curves of conductivity and Hall coefficient as a function of pressure have been fitted to a two conduction band model with various band parameters taken as adjustable. The curves thus fitted give consistent values of E12, the energy separation of the two bands, as a function of x. For (GaxIn1−x)Sb, the E12 values are in good agreement with those obtained previously from measurements as a function of temperature, no previous values having been published for Ga(AsxSb1−x). Approximate values for the ...
2 citations