SU1418628A1 - Method of determining distribution of space charge in dielectric-semiconductor structure - Google Patents

Abstract

This invention relates to electrical measuring technology. The purpose of the invention is to increase the measurement accuracy. The device implementing this method contains a semiconductor (PP) 1 under investigation, one side of which is grounded, and the other is covered with a dielectric layer 2, the thickness of which varies from zero to a predetermined value during production, as well as the measuring electrode 3 located near the surface PP 1 and connected to the meter 4 potential. The essence of this method is to measure the potential of the field of charge of the dielectric layer 2 for different thicknesses. To increase the accuracy of the measurement, in this method, the potential of the field of charge of the clean surface of the PP 1 is first measured, and then the distribution of the volume charge is calculated from a given fiber. 2 Il. (L

Description

l

1

The invention relates to electrical measuring equipment and can be used to measure the distribution of the volume charge in a dielectric layer of a dielectric-semiconductor structure,

The purpose of the invention is to increase the measurement accuracy.

Fig. 1 shows a structural electrical circuit of a device that implements a method for determining the distribution of a volume charge in a structure; Fig. 2 shows the energy diagram of the system; creeping conductor dielectric air - measuring electrode

A device that implements a method for determining the distribution of a volume charge in a dielectric structure

The volume charge Q / a), formed in the dielectric layer with thickness a, is associated with the compensation method

the measured voltage (potential) at given thicknesses of the dielectric layer (charge density on the outer surface of the dielectric layer due to its insignificant value is not taken into account) by the following expression:

and (x) and, - (x) dx. (3)

about

When semiconductor is oxidized, different values of U (a) are obtained, i.e. measure the voltage U (af) at different thicknesses of the dielectric layer and, by differentiating the expression (3) (U is assumed to be a constant value), receive;

The conductor contains the investigated semiconductor 1e, one side of which is grounded dielectric layer 2 which covers the opposite side of the semiconductor and whose thickness varies from zero to a predetermined value in the manufacturing process, the measuring electrode Ze located near the surface of the semiconductor (dielectric) and the potential measuring instrument 4 connected to measuring electrode

Method of determination: the distribution of the volume charge in the structure of the dielectric - semiconductor is as follows

The non-contact compensation method (FIG. 1) measures the potential arising between the surface of the semiconductor 1 5 still uncovered by the dielectric layer, and the measuring electrode 3, the thermodynamic work function E of which is known. Next, the absolute bend of the near-surface zones (f of semiconductor 1 (FIG. 2)) is determined by the expression

and

0 s

one

, - (. E -LE-EJ-UO

but

q - o - (j. - first component

(one)

charge ya

Q (0) 2 / 3qn D- () + A (e -1) + + (A - rMYT (2)

By this method, as well as by measuring the current-voltage characteristics and determining the charge of similar samples, it was established that the density of the volume charge arising in the dielectric layer on the face, e with a semiconductor, is equal in absolute value to the density of the calculated charge Q (0 ) in the near-surface layer of a semiconductor but with against a complicated sign

)but,

(four)

O () f F 1-.1-J-H, Sf / totj, /

 E-- where 0 / aj a.

The absolute sign of the charge Q; (a) is determined by the change (increase or decrease) dU (a) / da.

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Claims (1)

Invention Formula The method of determining the distribution of the volume charge in the structure of a dielectric semiconductor, including measuring the potential of the charge field of a dielectric layer for different thicknesses, in order to increase the accuracy of the measurement, measure the potential of the charge field of a clean semiconductor surface and the distribution volume charge calculated by the formula Q (aj) 2 / 3qn-: D- Che -1) + A (-1) + x -, -) vr., e.ii - l-js-, where D is the degree of doping of the semiconductor; q is the electron charge; n .. - own concentration semiconductor electrons; Y (is the normalized surface potential of the semiconductor; , 1 (E „. - -Ea-dE Yem bending of near-surface semiconductor zones; k is the Boltzmann constant; T is the absolute temperature of the semiconductor; E. about 1418628 electronic energy; C is the measured value of the potential for a clean surface of a semiconductor and a dielectric thickness E, the width of the forbidden zone of the semiconductor; energy between the Fermi level and the valence band ceiling; work output of the measuring electrode ;. the thickness of the dielectric layer after the 1st building, 1,2,3, ..., L (). O and Fie.2