CN100541651C

CN100541651C - A kind of bi-stable electric organic film and use its storer, overvoltage protection device

Info

Publication number: CN100541651C
Application number: CNB2003101082693A
Authority: CN
Inventors: 刘春明; 郭鹏; 蔡永挚; 徐伟
Original assignee: Fudan University
Current assignee: Fudan University
Priority date: 2003-10-30
Filing date: 2003-10-30
Publication date: 2009-09-16
Anticipated expiration: 2023-10-30
Also published as: CN1540667A

Abstract

The invention relates to a kind of heat erasable bi-stable electric organic film and application thereof with polarity memorizing effect.Film is the complex compound film of organic molecule material AOSCN and metal M, and M can be Cu, Ag etc.Film has good electrical bistable property and polarity memorizing effect, also has the heat erasable characteristic simultaneously.But this film can be used for preparation erasure information memory device and overvoltage protection device.

Description

A kind of bi-stable electric organic film and use its storer, overvoltage protection device

Technical field

The invention belongs to molecule electronic material and device technology field, be specifically related to a kind of heat erasable bi-stable electric organic film and application thereof with polarity memorizing effect.

Background technology

Organic electrical bistable material can be used for developing high density, high capacity information storing device and prepares organic logical device and logical circuit.Its characteristic is to have two kinds of different impedance states, and below threshold voltage, sample is a high-impedance state; When reaching threshold value, sample transits to low resistance state from high-impedance state in the extremely short time; After extra electric field is removed, still can keep low resistance state.The organic electrical bistable material that is most likely at recent acquisition widespread use is a charge transfer complex.([1] R S Potember, RC Hoffman and D O Cowan.Electrical Switching and Memory Phenomena in Cu-TCNQ ThinFilm.Apply Phys Lett, 1979,34:405; [2] W Xu, G R Chen, R J Li et al.Two New All-organicComplexes with Electrical Bistable States.Appl Phys Lett, 1995,67:2241; [3] E I Kamitsos andW M Risen.Optically Induced Transformations of Metal TCNQ Materials.Solid State Commum, 1983,45:165; [4] H Hoshino, S Matsushita and H Ssamura.Reversible Write-Erase Properties ofCu-TCNQ Optical Recording Media.Japan J Appl Phys, 1986,25:L341; [5] Yamaguchi S, Potember RS.Optical Spectroscopy and Scanning Tunneling Microscopy of Thin Films of theMetal-tetracyanoquinodimethane Derivatives.Syn Met, 1996,78:117). the advantage of these materials is that cheap easy acquisition is little with its device effect volume of making, but complex compound poor heat stability, crystallization easily, can erasablely not have the unidirectional drive characteristic with its device of making, limited application.

Summary of the invention

The objective of the invention is to propose a kind of bi-stable electric organic film that can wipe and have the unidirectional drive characteristic with electronically written, with heat, and propose the application of this membraneous material.

The bi-stable electric organic film that the present invention proposes is formed by organic molecule material AOSCN and metal M complexing.Metal M wherein adopts copper or silver; The compound name of organic molecule AOSCN is called 3, two (10-(dicyano methylene)-9-methylene anthryl)-2,4,8 of 9-, and 10-four thia spiral shell [5,5] undecanes, its chemical structural formula is as follows:

Molecular formula is C ₄₁H ₂₄N ₄S ₄, fusing point is above 300 ℃.Concrete its synthetic method of AOSCN can list of references ([6] xuwei, farming sky, Zhou Zhengrong, Tao Fenggang, Central China one, a kind of organic electronic material and preparation method thereof with thia spirane structure. Chinese patent application number is: 01127000.4)

Can keep stable for a long time under the AOSCN normal temperature in atmospheric environment, be easy to use the Vacuum Coating method film forming, and can form uniform amorphous thin film, because the singularity of molecular structure, this film is difficult for crystallization.

Thin-film device can prepare by vacuum evaporation method, and step is as follows: the thicker hearth electrode (such as Cu) of evaporation on the smooth substrate of cleaning, and then evaporation organic film AOSCN and top electrode Al successively, device architecture as shown in Figure 1.Substrate can have multiple, as microslide, piezoid, mica sheet etc.

The electrical bistable property of film, heat erasable characteristic and polarity memorizing effect characteristic test

(1) electrical bistable property of film

Measure and adopt HP33120 function generator, HP54645A digital oscilloscope, a series connection current-limiting resistance (1.1k Ω) between the hearth electrode of the top of appointment utilizes function generator to produce the square-wave pulse of 10V, measures electrical characteristics.Under 6V voltage, the transformation from the high-impedance state to the low resistance state takes place in film, and transition time, relaxation time was less than 1us less than 30ns.See Fig. 2, when film after high-impedance state transits to low resistance state, though between device two electrodes, apply what kind of electric pulse (＜10V), film remains low resistance state, i.e. the electrical characteristics of film time to time change not.

(2) the heat erasable characteristic of film

Thin-film device is after carrying out the height impedance transition, can not make it recover initial high-impedance state with electrical method, but with device in atmospheric environment 100-180 ℃ the baking more than 10 minutes, device can return to high-impedance state again, this high-impedance state can be transformed into low resistance state again under the voltage effect, low resistance state can revert to high-impedance state again under heat effect.Therefore, this thin-film device has the character that electronically written, heat are wiped, and can repeatedly repeat.The resistance value of low resistance state is usually less than 60 ohm, and the resistance value of high-impedance state and low resistance state ratio is usually greater than 1000 times.

(3) polarity memorizing effect of film

(suitable film thickness, base reservoir temperature, evaporating temperature, evaporation rate and electrode structure) film can form the Cu/AOSCN/Al sandwich construction of similar p-n junction under certain conditions.Different with general film, its electrical bistable property is relevant with the polarity of electrode.Utilize 10V, the electric pulse effect that 1us is wide, when Cu connects negative electrode, when Al connect positive electrode, device was just like the electrical characteristics shown in Fig. 3 line 2; Electric field is reverse, and promptly Cu connects positive electrode, and when Al connect negative electrode, device remained high-impedance state, shown in Fig. 3 line 1.If use 10V, the electric pulse effect that 1ms is wide, reversed electric field (Cu connects positive electrode, and Al connects negative electrode), device also can occur from high resistant to the transformation to low-resistance, but relaxation time is elongated, reaches tens microseconds or longer.The directional correlation of the electric field of electrical bistable property and application, this represents that this switching device has certain polarity memorizing effect.([7]Sato?C，Wakamatsu?S，Tadokoro?K?et?al.Polarized?Memory?Effect?in?theDevice?including?the?Organic?Charge-Transfer?Complex，Copper-Tetracyanoquinodimethane.Japan?J?Appl?Phys，1990，68：6535)

The bistable thin film that is formed by AOSCN and metal has the good electrical bistable behavior, and can heat wipe, and can be used for preparing high capacity information storing device and overvoltage protection device.

(1) scratch pad memory

This storer is a storage medium with the bi-stable electric organic film that organic molecule material AOSCN and metal M complexing form, and adopts cross spider version.Make metal M parallel lines (X-direction) on substrate, as hearth electrode, electrode material adopts Cu or Ag; Evaporation one deck AOSCN makes other layer of metal M parallel lines (Y direction) again on the AOSCN film then, and electrode material adopts Al.Two kinds of metal parallel lines state that is orthogonal, the intersection of each X-direction and Y direction be the storage unit (see figure 4).Because film has unidirectional on state characteristic, so can avoid preparing extra Schottky barrier, can simplify manufacture craft greatly.Wiping of device can be used general heating means, also can utilize laser instrument to heat and wipe, and can carry out heat by control laser head location and wipes such as writing data.

(2) overvoltage protection device

The bistable thin film that overvoltage protection device forms with organic molecule material AOSCN and metal M complexing is as the overvoltage protection medium, adopt cross spider version (Fig. 5) to make, utilize mask to prepare metal M parallel lines (X-direction) on substrate, electrode material adopts Cu or Ag; Evaporation one deck AOSCN then; Again mask is revolved and turn 90 degrees making other layer of metal M parallel lines (Y direction) on the AOSCN film, electrode material employing Al.Two kinds of metal parallel lines shape that is orthogonal.Directions X is connected with metal wire respectively with the lead end of Y direction.Directions X connects voltage, Y direction ground connection.When V surpassed threshold voltage, material changed low resistance state at once into, and X holds ground connection, and the overload electric current is passed through by bypass, and instrument has obtained protection.

Description of drawings

Fig. 1 is Cu/AOSCN/Al device architecture figure.

Fig. 2 is the electric bistable character of Cu/AOSCN/Al.

Wherein Fig. 2 (A) is the U-t curve, and Fig. 2 (B) is the I-U curve.

Fig. 3 is the polarity memorizing effect of Cu/AOSCN/Al.

Fig. 4 is the structural diagrams of storer.

Fig. 5 is the overvoltage protection device structural diagrams.

Embodiment

(1) scratch pad memory

On the wave carrier piece of cleaning, make metal Cu parallel lines (X-direction), as hearth electrode; Evaporation one deck AOSCN makes other layer of metal Al parallel lines (Y direction) again on the AOSCN film then.Two kinds of metal parallel lines state that is orthogonal, the intersection of each X-direction and Y direction be the storage unit (see figure 4).Vacuum tightness maintains 2 * 10 during evaporation ^-3Below the Pa, Cu adopts the molybdenum boat heating evaporation, and AOSCN evaporates with silica crucible, evaporation rate between 0.2 ~ 0.3nm/s, Al tungsten filament rapid evaporation.

The thin-film device that new preparation is changed without too high Low ESR 110 ℃ of bakings 1 hour in atmospheric environment, cooling back device changes kermesinus into by original pale red, but its electrical bistable property is identical with the electrical property that does not pass through heat treated thin-film device, and the electrical characteristics class of a curve is similar to Fig. 2.Device can not make it recover initial high-impedance state with electrical method after carrying out the height impedance transition, but with device in atmospheric environment more than 110 ℃ of baking 1h, device can return to high-impedance state again, high-impedance state can be transformed into low resistance state again under the voltage effect.The characteristic that this electronically written, heat are wiped can multiple conversions.Table one is listed the test result of device before and after baking, finds to have electrical bistable property same as shown in Figure 2.

Electrical characteristics before and after the thermal treatment of table one Cu/AOSCN/Al device

(2) overvoltage protection device

With chromic acid lotion soak, microslide after the washed with de-ionized water is as the evaporation substrate.On substrate, utilize mask to prepare metal Cu parallel lines bunch (X-direction); Evaporation one deck AOSCN then; Mask is revolved again and turn 90 degrees, make other layer of metal Al parallel lines bunch (Y direction) on the AOSCN film, pressure maintains 2 * 10 during evaporation ^-3Below the Pa, Cu adopts the molybdenum boat heating evaporation, and AOSCN evaporates with silica crucible, evaporation rate between 0.2 ~ 0.3nm/s, Al tungsten filament rapid evaporation.During protection of instrumentation, directions X connects voltage, Y direction ground connection.Threshold voltage is 6V, and the response time is 0.8-2.0us.

Claims

1, a kind of bi-stable electric organic film with polarity memorizing effect, it is characterized in that adopting organic molecule material AOSCN and metal M to form through the vacuum evaporation complexing, wherein the name of AOSCN is called: 3, two (10-(dicyano methylene)-9-methylene anthryl)-2 of 9-, 4,8,10-four thia spiral shells [5,5] undecane, metal M are a kind of of Cu, Ag.

But 2, a kind of erasure information storer, the bi-stable electric organic film that it is characterized in that forming with organic molecule material AOSCN and metal M complexing adopts cross spider version as storage medium, and X-direction is manufactured with the metal M parallel lines on substrate, as hearth electrode, wherein the name of AOSCN is called: 3, and two (10-(dicyano methylene)-9-methylene anthryl)-2,4 of 9-, 8,10-four thia spiral shell [5,5] undecanes, metal M is a kind of of Cu, Ag; Evaporation has one deck AOSCN film on it, and the Y direction on the AOSCN film is made other layer of metal Al parallel lines, as top electrode.

3, a kind of overvoltage protection device, the bistable thin film that it is characterized in that forming with organic molecule material AOSCN and metal M complexing is as the overvoltage protection medium, adopt cross spider version, X-direction is manufactured with the metal M parallel lines as hearth electrode on substrate, and wherein the name of AOSCN is called: 3, two (10-(dicyano methylene)-9-methylene anthryl)-2 of 9-, 4,8,10-four thia spiral shells [5,5] undecane, metal M are a kind of of Cu, Ag; Evaporation has one deck AOSCN film on it, and the Y direction on the AOSCN film is made other layer of metal Al parallel lines, as top electrode; Directions X is connected with metal wire respectively with the lead end of Y direction.