CN105552134A - Field effect diode - Google Patents

Abstract

The invention provides a field effect diode, comprising: a conductive layer, an insulating layer and a channel layer stacked in sequence; a first electrode and a second electrode in contact with the channel layer, and the second electrode is in contact with the conductive layer electrical connection. The field effect diode of the present invention has a high rectification ratio.

Description

field effect diode

technical field

The invention relates to the field of semiconductor devices, in particular to a diode.

Background technique

Since the bandgap width of silicon (1.12eV) and the bandgap width of germanium (0.66eV) are small, the PN junction diodes and Schottky junction diodes based on silicon and germanium have poor tolerance, that is, at high temperature and high temperature. There will be performance degradation problems when working under voltage, high current or light conditions.

In order to improve the tolerance of diodes, semiconductors with wide bandgap (that is, bandgap greater than 2eV) are usually used to prepare diodes, such as SiC with a bandgap of 3.2eV, GaN with a bandgap of 3.4eV, or ZnO with a bandgap of 3.4eV. However, wide bandgap semiconductors are difficult to be both N-type and P-type materials, so homogeneous PN junction diodes cannot be prepared. However, heterogeneous PN junctions have brought many problems due to poor interface quality. In addition, the wide bandgap semiconductor has a large electron affinity (usually greater than 4.2eV), and it is difficult to form a high Schottky barrier with common metals. The prepared Schottky diode has a large reverse current and poor rectification performance.

Contents of the invention

The technical problem to be solved by the invention is to provide a field effect diode.

Embodiments of the present invention provide a field effect diode, comprising:

Conductive layer, insulating layer and channel layer stacked in sequence;

a first electrode and a second electrode in contact with the channel layer, and the second electrode is electrically connected to the conductive layer.

Preferably, the first electrode and the second electrode are located on the same side of the channel layer.

Preferably, the channel layer is located between the first electrode and the insulating layer.

Preferably, the field effect diode further includes a conductive column in contact with side surfaces of the insulating layer and the channel layer, and the second electrode is electrically connected to the conductive layer through the conductive column.

Preferably, the second electrode includes two electrodes distributed on opposite sides of the first electrode.

Preferably, the second electrode is ring-shaped, and the first electrode is located at the center of the second electrode.

Preferably, the field effect diode further includes a substrate, and the conductive layer is located on the substrate.

Preferably, the field effect diode further includes an insulating substrate, and the first electrode and the second electrode are located on the insulating substrate.

Preferably, the conductive layer serves as the substrate of the field effect diode.

Preferably, the field effect diode further includes an electrode block located on the surface of the conductive layer.

Preferably, the channel layer is made of semiconductor materials that provide the same type of carriers.

The field effect diode of the present invention is a non-junction type diode, and does not have problems such as poor interface quality and large reverse current. The field effect diode has unidirectional conduction performance, and its rectification ratio is 3-4 orders of magnitude higher than that of silicon germanium diodes.

Description of drawings

Embodiments of the present invention will be further described below with reference to the accompanying drawings, wherein:

FIG. 1 is a cross-sectional view of a field effect diode according to a first embodiment of the present invention.

FIG. 2 is a graph of the volt-ampere characteristic of the field effect diode shown in FIG. 1 .

FIG. 3 is a rectification circuit diagram of the field effect diode shown in FIG. 1 .

FIG. 4 is a waveform diagram of the output voltage rectified by the field effect diode shown in FIG. 3 .

Fig. 5 is a cross-sectional view of a field effect diode according to a second embodiment of the present invention.

Fig. 6 is a cross-sectional view of a field effect diode according to a third embodiment of the present invention.

Fig. 7 is a sectional view of a field effect diode according to a fourth embodiment of the present invention.

Fig. 8 is a sectional view of a field effect diode according to a fifth embodiment of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings.

FIG. 1 is a cross-sectional view of a field effect diode according to a first embodiment of the present invention. As shown in FIG. 1 , the field effect diode 10 includes a glass substrate 11, an indium tin oxide conductive layer 12, an aluminum oxide insulating layer 13, and a zinc oxide channel layer 14 from bottom to top. The first electrode 151, the second electrodes 152, 152' disposed on opposite sides of the first electrode 151, and the conductive posts 162, 162' contacting the opposite sides of the aluminum oxide insulating layer 13 and the zinc oxide channel layer 14 . Wherein the second electrodes 152, 152' are electrically connected to the ITO conductive layer 12 through the conductive pillars 162, 162' respectively.

Since the indium tin oxide conductive layer 12/aluminum oxide insulating layer 13/zinc oxide channel layer 14 forms a metal/oxide/semiconductor capacitance (MOSCAP) structure, the positive voltage applied to the indium tin oxide conductive layer 12 is used for Adjust the concentration distribution of carriers (electrons) in the zinc oxide channel layer 14, so that the carrier concentration on the surface of the zinc oxide channel layer 14 (close to the aluminum oxide insulating layer 13) increases, thereby forming a conductive channel (ie, a conductive channel track open), so there is current between the second electrodes 152, 152' and the first electrode 151. When a positive voltage is applied to the first electrode 151 , the carriers in the conduction channel will be depleted (that is, the conduction channel is closed), and the field effect diode 10 is in a reverse cut-off state at this time. FIG. 2 is a graph of the volt-ampere characteristic of the field effect diode shown in FIG. 1 . Wherein the second electrodes 152 and 152' are used as positive electrodes, and the first electrode 151 is used as negative electrodes. It can be seen from FIG. 2 that as the voltage on the positive electrode increases, the current in the field effect diode 10 (ie, the forward current) increases rapidly. However, the reverse current in the field effect diode 10 does not increase as the voltage increases. The field effect diode 10 of this embodiment has unidirectional conductivity, and its rectification ratio is about 5×10 ⁸ , which is 3-4 orders of magnitude higher than that of silicon germanium diodes.

FIG. 3 is a rectification circuit diagram of the field effect diode shown in FIG. 1 . The waveform generator 1, the field effect diode 10 and the resistor 2 with a resistance value of 15 MΩ are connected in series, and the oscilloscope 3 is connected to both ends of the resistor 2 for measuring the output voltage at both ends of the resistor 2.

FIG. 4 is a waveform diagram of the output voltage rectified by the field effect diode shown in FIG. 3 . As shown in FIG. 4 , the input voltage provided by the waveform generator 1 is a series of sinusoidal alternating currents with different amplitudes, and the output voltage is a series of positive polarity voltage signals with different amplitudes. The field effect diode 10 filters the negative half cycle of the sinusoidal alternating current, thus realizing the function of half-wave rectification.

The method of manufacturing the field effect diode 10 will be briefly described below. First, radio frequency magnetron sputtering technology is used to prepare an indium tin oxide conductive layer 12 with a thickness of 100 nanometers on a clean glass substrate 11, and then an oxide film with a thickness of 50 nanometers is prepared on the indium tin oxide conductive layer 12 using atomic layer deposition technology. The aluminum insulating layer 13 is patterned, and a zinc oxide channel layer 14 with a thickness of 50 nanometers is prepared and patterned on the aluminum oxide insulating layer 13 using radio frequency magnetron sputtering technology. Deposit an indium tin oxide electrode layer on the zinc oxide channel layer 14 to form conductive pillars 162, 162' in contact with the two sides of the aluminum oxide insulating layer 13 and the zinc oxide channel layer 14, and finally use ultraviolet lithography to make the zinc oxide The ITO electrode layer on the channel layer 14 forms a first electrode 151 and a second electrode 152, 152'.

FIG. 5 is a cross-sectional view of a field effect diode 20 according to a second embodiment of the present invention. It is basically the same as FIG. 1 , the difference is that the first electrode 251 is located at the center of the ring-shaped second electrode 252 . When a forward conduction voltage is applied between the second electrode 252 and the first electrode 251, the carriers in the conductive channel move from the center of the conductive channel of the zinc oxide channel layer 24 to the surroundings, compared to the field effect The diode 10 increases the area of the conductive channel, thus reducing the forward conduction resistance of the field effect diode 20 . Its working principle and rectification performance are the same as those of the field effect diode 10, and will not be repeated here.

6 is a cross-sectional view of a field effect diode 30 according to a third embodiment of the present invention, which is basically the same as in FIG. Since the indium tin oxide conductive layer 32 electrically connected to the second electrodes 352, 352' is located on the uppermost layer of the insulating substrate 31, it is very convenient to weld electrode leads (not shown in FIG. 6 ) on the indium tin oxide conductive layer 32 . When a positive voltage is applied on the conductive layer 32, a conductive channel is also formed on the surface of the zinc oxide channel layer 34 (close to the aluminum oxide insulating layer 33), and its working principle and rectification performance are the same as those of the field effect diode 10, and are not described herein. Let me repeat.

7 is a cross-sectional view of a field effect diode 40 according to a fourth embodiment of the present invention, which is basically the same as in FIG. 1, except that the field effect diode 40 has a conductive substrate 41 made of stainless steel. In addition to being used as the substrate, it is also used as the conductive layer in the field effect diode 40 (that is, the metal in the MOSCAP structure), so the preparation process of the conductive layer on the conductive substrate 41 is omitted, and the cost is low and the structure is simple. After a positive voltage is applied on the conductive substrate 41, a conductive channel is also formed on the surface of the zinc oxide channel layer 44 (close to the aluminum oxide insulating layer 43), and its working principle and rectification performance are the same as those of the field effect diode 10, here No longer.

FIG. 8 is a cross-sectional view of a field effect diode according to a fifth embodiment of the present invention, which is basically the same as FIG. 7 , except that the field effect diode 50 further includes an electrode block 52 disposed on a conductive substrate 51 . Welding the electrode leads (not shown in FIG. 8 ) to the electrode block 52 can obtain greater tensile strength and avoid the problem of falling off caused by the direct connection between the electrode leads and the conductive substrate 51 .

According to other embodiments of the invention, the field effect diode has more or less than two second electrodes.

According to other embodiments of the present invention, the conductive pillar may be made of a conductive material different from that of the second electrode and the conductive layer, as long as an electrical connection can be formed between the second electrode and the conductive layer.

Based on the above working principle of the field effect diode of the present invention, those skilled in the art know that the channel layer materials in the above embodiments include but are not limited to silicon, germanium, indium oxide, indium zinc oxide, indium gallium zinc oxide, nitride Gallium, silicon carbide, pentacene, rubrene, high 3-hexylthiophene, graphene, molybdenum disulfide and other semiconductor materials. The material of the first electrode and the second electrode is not limited to indium tin oxide, but may also be conductive metal or conductive metal oxide, such as gallium zinc oxide (GZO), aluminum zinc oxide (AZO) or fluorine tin oxide (FTO). The material of the insulating layer is not limited to aluminum oxide, and may also be insulating materials such as silicon oxide, silicon nitride, hafnium oxide, zirconium oxide, and polymethyl methacrylate. The substrate material is not limited to glass, and may be silicon, sapphire, polyimide, polyethylene naphthalate, polyethylene terephthalate, or the like.

Although the present invention has been described in terms of preferred embodiments, the present invention is not limited to the embodiments described herein, and various changes and changes are included without departing from the scope of the present invention.

Claims (11)

1. A field effect diode, characterized in that, comprising: Conductive layer, insulating layer and channel layer stacked in sequence; a first electrode and a second electrode in contact with the channel layer, and the second electrode is electrically connected to the conductive layer. 2. The field effect diode according to claim 1, wherein the first electrode and the second electrode are located on the same side of the channel layer. 3. The field effect diode according to claim 2, wherein the channel layer is located between the first electrode and the insulating layer. 4. The field effect diode according to claim 1, characterized in that, the field effect diode further comprises a conductive pillar contacting the side surfaces of the insulating layer and the channel layer, and the second electrode passes through the conductive pillar electrically connected to the conductive layer. 5. The field effect diode according to claim 1, wherein the second electrode comprises two electrodes distributed on opposite sides of the first electrode. 6. The field effect diode according to claim 1, wherein the second electrode is in a ring shape, and the first electrode is located at the center of the second electrode. 7. The field effect diode according to any one of claims 1 to 6, characterized in that, the field effect diode further comprises a substrate, and the conductive layer is located on the substrate. 8. The field effect diode according to any one of claims 1 to 5, characterized in that, the field effect diode further comprises an insulating substrate, and the first electrode and the second electrode are located on the insulating substrate . 9. The field effect diode according to any one of claims 1 to 6, characterized in that the conductive layer serves as a substrate of the field effect diode. 10. The field effect diode according to claim 9, characterized in that, the field effect diode further comprises an electrode block located on the surface of the conductive layer. 11. The field effect diode according to any one of claims 1 to 6, characterized in that, the channel layer is made of semiconductor materials that provide the same type of carriers.