JPH02170471A - High-speed diode - Google Patents

Abstract

PURPOSE:To obtain a high-speed diode of desired characteristics by a combination of liketime killers by a method wherein electrodes installed respectively in a plurality of regions into which different lifetime killers have been introduced are used and connected in parallel. CONSTITUTION:A P-N junction face 3 by a P-layer adjacent to an N-layer 1 exists in a silicon substrate; a groove 4 exceeding a depth of the face 3 from the surface of the substrate is formed; the groove 4 is filled with an insulator 5. As a result, the Player is divided into two regions 21, 22. Au is diffused and introduced into the region 21; Pt is diffused and introduced into the region 22. In addition, a cathode electrode 6 is applied to the N-layer 1 ; anode electrodes 71, 72 are applied respectively to the regions 21, 22; after that, the electrodes 71, 72 are connected. Thereby, it is possible to obtain a constitution where diodes 11, 12 composed of the N-layer 1 and the P-layer 21 as well as the N-layer 1 and the P-layer 22 are connected in parallel. In this manner, a high-speed diode which can relax a detect of any diodes can be formed on a single semiconductor substrate; the obtained diode always reduces an overall loss.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-speed diode in which a lifetime killer is introduced into a semiconductor body to shorten reverse recovery time for use in high-frequency rectification and the like.

[Conventional technology]

Gold, platinum, or the like was used as a lifetime killer introduced into the semiconductor element so that carriers within the semiconductor element disappeared rapidly.

[Problem to be solved by the invention]

In conventional high-speed diodes, when used at high frequencies, switching loss due to transient forward voltage increases, and high-temperature reverse current is large, resulting in excessive loss. there were.

On the other hand, elements using pt as a lifetime killer are
Since the steady-state forward voltage is large, there is a problem in that the loss is large.

The object of the present invention is to solve the above-mentioned problems and to provide a high-speed diode in which the drawbacks caused by the introduction of a lifetime killer are alleviated.

[Means to solve the problem]

In order to solve the above problems, the high speed diode of the present invention has at least one layer in contact with the PN junction that is insulated from each other and divided into a plurality of regions in which different lifetime killers are introduced, and an electrode in each region. shall be provided.

[Effect]

By connecting a plurality of regions in which different lifetime killers have been introduced in parallel using electrodes provided in each region, the drawbacks caused by the introduction of the lifetime killer can be offset and its adverse effects can be alleviated.

〔Example〕

FIG. 1 (71), rb) shows a high-speed diode according to an embodiment of the present invention in a vertical cross-sectional view and a plan view. A PN junction surface 3 exists due to the adjacent P layer, but a groove 4 with a depth exceeding the PN junction surface 3 is formed from the surface of the substrate by etching or sand cutting, and an insulating material 5 such as glass is formed in the groove 4. Filled. Note that this is performed after the mesa enching step, and as a result, the P layer is divided into two regions 21 and 22. Then, Au is diffused into the region 21 and Pt is diffused into the region 22. The cathode electrode 6 is in the NJll, the first seventh node electrode 71 is in the two-layer region 21, and the
A near-node electrode 72 is attached to the surface of each of the 18N regions 22 . If two anode electrodes 71 and 72 are connected, a diode consisting of NJWI and one layer 21 and N
11l and a diode consisting of two layers 22 are connected in parallel. The former diode is 11. Assuming that the latter diode is 12, the time characteristics of the transient forward voltage will be as shown in FIG. 2 by the solid line and the dotted line in the latter case. When two diodes are connected in parallel and used at high frequencies, as shown in Figure 2), the transient current of about 2 μ or less can be handled by the PT introduction diode 12 with a low transient forward voltage, and the steady state of about 21 m or more can be handled. Au with low steady-state forward voltage
The introduction diode 11 takes care of this. Figure 3 +Il+ shows the reverse recovery current time characteristics, the solid line shows the characteristics of diode 11, and the dotted line shows two types of characteristics of diode 12. When the two diodes are connected in parallel, the reverse recovery time t□ of diode 11 When is greater than trr of diode 12, the reverse recovery operation characteristic is that of diode 11, as shown in Figure 3).
When t□ of the diode 11 is smaller than t of the diode 12, the characteristic becomes a composite of both as shown in FIG. Note that since the silicon single crystals used are common, they have the same specific resistance, and the reverse breakdown voltage characteristics of both diodes are the same, so no unbalance occurs.6. When used at high frequencies, the transient time of the forward current is handled by a PT-introduced diode with a low transient forward voltage, and the steady-state time is handled by a ^ua single diode with a low forward voltage, which mainly reduces forward loss. Furthermore, since the reverse characteristics are handled by a PT-introduced diode with low high temperature reverse current, the overall loss is reduced.

FIG. 4 shows another embodiment of the invention in plan view, with two p
111 regions 21 and 22 are divided by annular grooves filled with an insulator 5. Note that electrodes are not shown in this figure.

〔Effect of the invention〕

According to the present invention, by forming a plurality of high-speed diodes in which different lifetime killers are introduced in one semiconductor and insulating them from each other so that they can be connected in parallel, it is possible to By using different lifetime killers with different characteristics, a high-speed diode in which the shortcomings in the characteristics of either diode are alleviated can be formed within a single semiconductor substrate. Furthermore, it is also possible to obtain high-speed diodes with novel characteristics by combining other lifetime killers.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) show an embodiment of the present invention, and (a)
(1) is a vertical cross-sectional view, (1) is a plan view, (bl is a diagram showing the forward operating characteristics of an Au-introduced high-speed diode and a PT-introduced high-speed diode, and (4) is a diagram in each case, - )
is the case of the embodiment of the present invention, and FIG. 3 is a diagram showing the reverse recovery operation characteristics of both diodes, and (a) is for each case. (bl, (C1 is an embodiment of the present invention; FIG. 4 is a plan view showing another embodiment of the present invention.

Claims (1)

[Claims] (1) A high-speed diode characterized in that at least one layer in contact with the PN junction is insulated from each other and divided into a plurality of regions into which different lifetime killers are introduced, and each region is provided with an electrode.