JPS6236859A - Schottky barrier diode - Google Patents

Abstract

PURPOSE:To improve the reverse withstanding voltage by forming a Schottky electrode on a recess of an operating layer grown on a dug high conductive layer to increase the contacting area at the periphery of the electrode to be readily concentrated in an electric field. CONSTITUTION:A Schottky electrode 4 is contacted with a recess of an operating layer 3 grown on a high conductive layer 2 dug by etching to form a Schottky barrier. An ohmic electrode 5 is contacted with the layer 2 by removing the prescribed portion of the layer 3. Since the contacting area with the operating layer is larged at the periphery of the Schottky electrode in which an electric field is readily concentrated, the concentration of the electric field hardly occurs. In other words, the leakage current decreases to improve the reverse withstanding voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a Schottky barrier diode suitable for high frequency operation.

Semiconductor devices using conventional Schottky barrier technology are fast switches because the accumulation effect of minority carriers can be ignored.

It is suitable for high frequency operation, and the characteristics have been improved in the past.
The conductive layer r32 and the n-type GaAs active layer are epitaxially grown continuously, and a Schottky electrode is formed on the surface of the n-type GaA3 active layer (through), and the required portions of the n-type GaAs active layer (through) are removed and exposed. n′-type GaAS conductive layer G
This is a Schottky barrier diode with an ohmic electrode (351 gold) provided on the surface of 2. (2) is an insulating film that insulates the active layer and the electrode outside the contact area.A conductive layer G2 with high impurity content is provided. By attaching an ohmic electrode O!i) to this conductive layer 02, the series resistance is reduced and the characteristics of the diode are improved.

However, because the electric field concentrates around the Schottky electrode, leakage current increases and reverse breakdown voltage decreases.

C) Problems to be Solved by the Invention The present invention has been made in view of the above-mentioned points, and it is an object of the present invention to provide a buyot-kibarrier diode with low series resistance and good reverse breakdown voltage.

2. Means for Solving the Problems The present invention provides a Schottky structure in which an active layer is grown on a highly conductive layer with a high degree of impurity, a Schottky electrode is provided on the surface of the active layer, and an ohmic electrode is provided on the surface of the high conductive layer. In the barrier diode, a highly conductive layer is dug in the Schottky electrode and grown on it, forming the recess F of the -fc active layer.

e) Operation Since the contact between the Schottky electrode and the active layer is made in a concave shape, electric field concentration around the Schottky electrode is eliminated.

To J Example FIG. 1 is a schematic diagram of an embodiment of the present invention.

11+ is an n-type CaAs substrate (21 is an n++-type GaA with high impurity If epitaxially grown on the substrate)
s high conductivity layer, (31 is an n-type GaAs active layer epitaxially grown on the high conductivity layer 121, (4 is T1-P
Schottky electrode made of t-Au, (5) is Au-aθ
-N1 ohmic electrode (61 is an insulating film of 5i029, which insulates the active layer other than the contact area and each electrode.A Schottky electrode (4) is formed on the highly conductive Fii$121 formed by etching. The ohmic electrode (51
A predetermined portion of the active layer 13+ is removed to contact the highly conductive layer (2).

In such a Schottky barrier diode, since the contact area with the active layer is large in the peripheral area of the Schottky electrode where electric fields tend to concentrate, electric field concentration is less likely to occur, that is, leakage current is reduced and reverse breakdown voltage is improved. .

The manufacturing process of the Schottky barrier diode of the present invention will be explained along FIGS. 2A to 2EK. First, an n++ type GaAs highly conductive layer 12+ with a high impurity concentration is epitaxially grown to a total thickness of about 12 μm by vapor phase growth on an n+ type GaA3 substrate Ill (Fig. 2A).A resist ( 7) Open the window in the designated area *(2a) with et cloth,
The highly conductive layer 12 is etched to a total depth of about 1.5 μm using gold tartaric acid etchant (FIG. 2B). The resist (7) is removed and n-type GaAS! is deposited on the highly conductive layer (2). The l11/ll' layer 131' is made thinner (for example, 2
000A) Epitaxial growth. At this time, Figure 2C
As shown in the figure, the active layer f3+ has a concave shape in the predetermined region (2a).

Then, SiO2@ as an insulating film is formed on the operating layer (31)
f61 is deposited by CVD method. The 5102 film (61) is patterned using a resist in the same manner as described above, and the active layer 131 is etched until the highly conductive layer (21) is exposed to provide an ohmic electrode (FIG. 2D).

Au-Go-Nit-1 is applied to the exposed high conductive layer (2).
! ! An ohmic electrode (51) is formed by selectively depositing the 5iO211 on the concave portion of the active layer +31.
1! The Schottky electrode 141 is formed by selectively depositing Ti-Pt-Auli (second
Figure E), the Schottky barrier diode is completed.

In this embodiment, GaAs1 is used as the semiconductor, but any other semiconductor may be used as long as it can form a Schottky barrier.

g) Effects of the Invention As is clear from the above description, in the present invention, the Schottky electrode is in concave contact with all the active layers.

Since the contact area is widened at the periphery of the Schottky electrode where electric fields tend to concentrate, electric field concentration does not occur.

Therefore, the leakage current is reduced, and the reverse breakdown voltage is improved while maintaining the structure with small series resistance.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the present invention, FIG. 2 is a manufacturing process diagram of a Schottky barrier diode according to the present invention, and FIG. 3 is a schematic diagram of a conventional Schottky barrier diode. 111-n+ type GaA3 substrate%+21-n”+ type Ga
AS high conductivity layer, (3T...n-type GaAs operating layer, (4)
...Schottky electrode, (51...O2Fuku electrode.

Claims (1)

[Claims] 1) In a Schottky barrier diode in which an active layer is grown on a highly conductive layer with a high impurity concentration and a Schottky electrode is provided on the surface of the active layer and an ohmic electrode is provided on the surface of the highly conductive layer, the Schottky electrode is formed by digging the highly conductive layer. A Schottky barrier diode, characterized in that the Schottky barrier diode is formed on a concave portion of an active layer grown thereon.