JPS5846680A - Memory element - Google Patents

Abstract

PURPOSE:To eliminate restriction resulting from domain size of plarization by introducing thin films for all elements comprising ferro-dielectric material, realize micro-dimensions of elements by simplifying the structure and to improve inversion speed of polarization by vertically applying a write voltage to the film surface. CONSTITUTION:The write electrode 4, ferro-dielectric thin film 1b, semiconductor thin film 2a, insulating thin film 10 and write electrode 4 are laminated on the insulating substrate 9 and the read electrode 5 is provided at both ends of semiconductor thin film 2a. A conductivity between the read electrodes 5 is determined in accordance with charge density in the semiconductor thin film 2a and polarity thereof. When the semiconductor thin film is n type, it becomes conductive for minus charge but non-conductive for plus charge. In addition, an insulating thin film 10 is inserted between the semiconductor thin film 2a and write electrode 4 in order to prevent change of conductivity, namely drop of read output signal. A memory element is formed into the 2-terminal structure and further the structure of memory plane composed of the word lines and bit lines is simplified. Thereby, high integration density is realized and operation speed as the memory plane can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a strong electric storage element, and particularly to miniaturization and speeding up of the element.

As a conventional ferroelectric memory element, as shown in FIG.
A common electrode 8, a protrusion W11 pole 5, and a protrusion No. 1.1 billion are formed in the opposite direction of the substrate.

A field effect transistor is formed on the semiconductor substrate 2b as shown in FIG. (drain electrode) 5. and write electrode (gate electrode) 4. In the former, the polarization domain cannot be made smaller due to the thickness of the ferroelectric material, making it impossible to miniaturize the element. Although the latter is relatively easy to miniaturize, the structure is complicated due to the Aa!#Jf expansion layer 6 of the source and drain and the relatively large field acupuncture film 7 formed on both sides thereof. , there are constraints on miniaturization.In both cases, the current path during infiltration is in the lateral direction of the semiconductor region as shown by arrow 8 in Figure 1a) e (b), and the resistance value is high. The speed of polarization reversal becomes slower.

The purpose of the present invention is to eliminate the above-mentioned limitations and provide an element structure that can be made faster and faster. ◎ Figure S - shows the structure of the present invention, and the electrode number is inserted into the insulator substrate 9, the strong conductor thin NX1b1 and the thin conductor MXZ.
As insulator thin film 10 Inserted t virtue 4t - laminated,
Protrusions 11 and poles 5 are provided at both ends of the semiconductor thin film 2a.

The first feature of the present invention is to thin the entire *g'a' layer including the strong peaks and electric bodies as described above, remove the restriction due to the domain size of polarization, and make the structure finer by semi-roping. In addition, the speed of polarization reversal is improved by setting the applied force direction of the stored voltage to -1 between the membranes as shown by arrow 8 in the @S diagram (ml).

Figure 3 (- and lcj correspond to "l" and 101 of the 8-value polarization, respectively, and the charge density of each layer in the fc storage state ±
FIG. The conductivity between the readout electrodes 5 is determined by the charge density in the semiconductor thin film 2a and its polarity; when the semiconductor thin film is n-type, it is conductive when it has a negative charge;
The semiconductor thin film 2 becomes non-conductive when it has a positive charge.
When the aK@loaded charge + fi4 is directly stacked, the charge in the semiconductor thin film is canceled out by the charge generated on the same electrode, and the charge density becomes the distribution shown by the dotted line in Fig. 3, 1bJ, lc). The conductivity change between the readout electrodes becomes significantly smaller. Therefore, the second feature of the present invention is the semiconductor thin n5t
An insulator 4Jil[10 is inserted at the threshold between =a and the incoming electric power to prevent a decrease in the conductive event fj in the 1fm period, that is, a decrease in the readout output information.

The 41F mold in Part 8 of the present invention is implemented by forming the present memory element into a 24-child structure as described later, and by forming a mesoriplane structure consisting of a matrix of words and bits into a single matrix. This is intended to improve the operating speed of the memory plane by measuring lIf and high density f.

Next, a practical example of the present invention will be explained based on the ag2 diagram. First, Aj was applied to a clean glass base &9 by vacuum evaporation method.
The write electrode 4 is formed by applying a crushing current of about 1000 A to a normal photoetching technique.

Next, a layer of about 1 μm of ERI YM a O@ is applied by high frequency sputtering to form a strong brocade electric material 771b, and then a layer of n-type amorphous silicon is applied to about 0.5 μm by plasma OV Dfi to form a semiconductor layer 2a. . Plasma OV
The temperature of the substrate in D is about 200° C., which is lower than that when a normal polysilicon enclosure is applied. Next, the thin layers lb and 2a are formed into the same pattern by plasma etching using freon gas. Next 8i
0. A layer of 0.571 m was formed by high-frequency sputtering, and an absolutely solid layer 10 was formed by photo-etching 6 technology. Finally, U is approximately 1 by vacuum 4 layer transfer
000A is deposited, and an electrode 5 is formed using a photo-etching technique.

FIG. By connecting the embedded electrode with a conductor film, it has a two-terminal structure so that writing and reading can be performed using the same electrode.This example is similar to the previous example, in which a strong cast electric thin film and a semiconductor thin film are combined in one stream. By separately patterning the areas formed in the - pattern, providing a step at one end as shown in Fig. 8, and additionally forming a resistive thin film by sputtering Ta there, the same pressure as in the previous example is applied. The device of this example can be formed using the following steps.

In this case, the resistance thin film 11Fc causes a slight loss in cutting in and extending out, but as shown in FIG. 184, the structure is extremely simplified and the memory plane can be made highly dense and straight. Therefore, it is possible to improve the operating speed of the filter.

In addition, in the above example, YMnOHt was used as the ferroelectric material dilution.
-te was used, but BrMnO1sHoMnO@@TmM
n0@*Y b M o O@ and L u M n
O@ can also be used for orchid Q

[Brief explanation of the drawing]

M1 Figures 1a) - (b) are the conventional structure, Figure 2 (- is the SAh example according to the present invention, Figure 8 tb+e4c) is the distribution of charge density ±Q in the configuration of the present invention, and 8 and 4 are diagrams showing other embodiments. Here l-1
1b is a strong electric conductor board, 1b is a strong electric conductor #armpit, 21 is a cow conductor thin film, sb is a cow conductor board, 8 is a common electrode, No. is a lead-in electrode, 5 is a protrusion electrode, and 6 is a high-wire conductor board. Longitudinal wave scattering layer, 7 is a field oxide film, 8 is 4 @ direction of flow of current, 9 is a glass substrate, 10 is a thin film of lint, 11 is a resistive thin film, 12//i
Word #5lll is pit-1l function is tl element, l
5#'i memory grain.

Claims (1)

[Claims] (1) Bringing a ferroelectric substance and a semiconductor into @ contact, and changing the carrier concentration of the cough semiconductor by polarization of the ferroelectric substance 4
1. In a brocade electromechanical memory element, an electrode thin film, a fermented electrolyte thin film, a semiconductor thin film, an insulator thin film, and an electrode thin film are laminated on an insulating substrate in the order described herein, or in the reverse order of the present description. A memory element characterized in that it is formed by. 12) A device having a stacked layer of an electrode thin film, a strong electrical conductor thin film, a semiconductor thin film, an insulator thin film, and an electrode thin film, each of the electrode thin films being used as an electrode, and a pair of readout electrodes provided on the stn semiconductor thin film. T! In Motoko. One reading comparison electrode is connected to one of the input electrodes with a thin film of resistance, the other d extraction electrode is connected to the other input electrode with a thin film of low resistance, and both write electrodes are connected to 8 terminals. A memory element having a structure characterized by nine things. (3) Ferroelectric lIIIM7& is YMo (J @
* lii r Mu U @ * HnMn O@
TenMn0@*YbMn0@i or L u Mn U
The mlj element 0 described in item 1 or 2 of the scope of patent d#, characterized in that it is a thin film of one of the following:
(4) The memory element according to item 1 or 2, characterized in that the semiconductor thin film is an amorphous silicon thin film. ,