SU1168019A1 - Method of determining mobility of charge carriers - Google Patents

Abstract

A METHOD FOR DETERMINING MOBILE CARRIER MEDIA, based on creating two electrodes on a test sample, one of which is collector, and the second injecting, applying voltage pulses to electrodes, registering the transient injection current and determining the drift mobility of charge carriers by calculation, differing from that, in order to increase accuracy, speed and non-destructive testing, the second electrode is made in the form of a two-layer structure consisting of a dielectric layer Thickness of O, 1 to 1 mm, coated with a metal film, is applied to the electrodes rm hundred direct voltage having a magnitude and polarity, providing enriched layer creating charge carriers in the semiconductor boundary - dielectric.

Description

1 1 The invention relates to semiconductor technology and can be used to control the parameters of semiconductors, in particular to determine the drift mobility of charge carriers. The purpose of the invention is to show accuracy, efficiency and non-destructive testing. FIG. 1 shows a scheme for implementing the method; in fig. 2 shows the band diagrams of the semiconductor – dielectric structure for the case of Vj. 0; in fig. 3 - for the case of V-0; in fig. 4 shows the dependence of the transient current I (t) on time t. FIG. 1 the following notation is accepted: pulse generator 1, output impulse generator 2, constant bias source 3, metal electrode 4. dielectric 5, (semiconductor 6, callor electrode 7, measuring device input resistance 8. FIGS. 2 and 3 the notation indicates the bias voltage V, the bottom of the conduction band E, the bottom of the valence band Ey, Fermi level F. Example: The drift mobility of electrons in the structure Me - SiOj - Si was determined on the basis of high-resistance silicon with a specific resistance p 2 -10 Ω cm. Thickness SiOj, composition l la 0.2 µm. Silicon 19.1 substrate thickness 210 µm, structure area 310 cm. Displacement voltage V ranged from 3 to 6 V. Figure 4 shows the experimentally obtained dependence of the transient current on time when voltage pulses are applied. There is a sharp peak due to capacitive perturbation in the transient process. The second peak corresponds to the arrival time of the leading edge of the charge carrier packet to the collector electrode (26 n). A further slow decline is due to the depletion of the charge in the enriched layer of silicon. The drift mobility of charge carriers was calculated by the formula where a is a coefficient equal to 1 for currents not limited by spatial charge, and a% 0.78 for currents limited by spatial charge; - arrival time of the leading edge of the charge carrier packet to the collector electrode} L - thickness of the semiconductor. At а 0.78, the calculated value of the drift mobility of charge carriers is equal to / Kj 1320.

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Claims (1)

METHOD FOR DETERMINING THE MOBILITY OF CHARGE CARRIERS, based on the creation of two electrodes on the test sample, one of which is collector and the second injection, applying voltage pulses to the electrodes, registering the transient injection current and determining the drift mobility of charge carriers by calculation, characterized in that, s In order to improve accuracy, efficiency and ensure non-destructive testing, the second electrode is made in the form of a two-layer structure consisting of a thick dielectric layer d from 0.1 to 1 μm, covered with a metal film, a constant voltage is applied to the electrodes, having a magnitude and polarity, which provides a layer of charge-enriched charge at the semiconductor-insulator interface. НГ5ШТ ^ПО_ П ^ · eleven