JP2547759Y2 - MES type compound semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a MES type compound semiconductor device, and particularly to a protection structure against surge voltage.

[Related Art] A MES type compound semiconductor device using GaAs or the like has an unavoidable disadvantage due to its structure that the gate breakdown voltage is lower than that of a MOS type semiconductor device.

For this reason, in this type of MES type compound semiconductor device, it is necessary to take measures to prevent malfunction due to a surge voltage applied to the gate electrode and reduce damage.

As a means for compensating the gate withstand voltage, a device having a structure in which protective diodes 4 and 5 are provided between gate electrodes 1 and 2 and a source electrode 3 as shown in FIG. If an excessive surge voltage is applied to the gate electrode 1 or 2, a surge current flows to the source electrode 3 due to breakdown of the protection diode 4 or 5 when an excessive surge voltage is applied to the gate electrode 1 or 2. The current is prevented from flowing to the drain electrode 10.

When such a structure is realized on a semiconductor substrate, as shown in FIGS. 3 to 5, the gate electrodes 1, 2
An n-type impurity region 7, a p-type impurity region 8, and an n-type impurity region 9 are provided on a substrate 6 between the semiconductor device 1 and the source electrode 3, whereby the pn-type impurity region 7 and the p-type impurity region 8 Conventionally, it is generally considered that a protection diode 4 and a pn-type protection diode 5 including a p-type impurity region 8 and an n-type impurity region 9 are provided in series with their directions reversed.

[Problem to be Solved by the Invention] In the above-described conventional structure, the junction surface between the n-type impurity regions 7 and 9 of the protection diodes 4 and 5 and the p-type impurity region 8 is straight, so that the current flow path area is sufficient. Could not be secured. For this reason, there is a problem that the surge current cannot fully flow through the source electrode 3 and the function as the protection diode cannot be sufficiently achieved.

The present invention has been made in view of the above circumstances, and has as its object to achieve an improvement in surge withstand voltage in a MES type compound semiconductor device.

[Means for Solving the Problems] The present invention focuses on the fact that the surge withstand voltage can be improved by increasing the flow area of the surge current in the protection diode, and two pns are provided between the gate electrode and the source electrode.
Type protection diodes are provided in series with their directions reversed,
The two junction surfaces formed by the n-type impurity region and the p-type impurity region of the protection diode have a waveform shape, and the junction length in a direction orthogonal to the direction of the diode is substantially the same. Is a MES type compound semiconductor device.

[Operation and Effect of the Invention] By making the junction surface between the n-type impurity region and the p-type impurity region of the protection diode provided between the gate electrode and the source electrode a non-linear shape such as a comb shape, The flow path area for the surge current is increased, the resistance is reduced, and the surge current efficiently flows to the source electrode. Therefore, in the MES-type compound semiconductor device, the function of the protection diode can be sufficiently exhibited, and the surge withstand voltage can be improved.

When simply increasing the bonding surface in a linear shape, the semiconductor chip must be enlarged accordingly, but when the bonding surface is formed in a corrugated shape, the semiconductor chip does not need to be enlarged. The joining area can be increased.

[Embodiment] The present invention will be specifically described based on an embodiment shown in FIG. FIG. 1 is a plan view showing the structure of the protection diode portion corresponding to FIG. 5 described above, and the same reference numerals in FIG. 1 denote the same parts as in the prior art.

As shown, an n-type impurity region 7 on the gate electrode 1 or 2 side provided on a gallium arsenide (GaAs) substrate 6 is provided.
4a (shown by oblique lines in the figure) between the n-type impurity region 9 and the p-type impurity region 8 on the side of the source electrode 3 is formed in a waveform. (Indicated by oblique lines in the figure) also has a waveform shape.

As a result, the junction area between the n-type impurity region 7 and the p-type impurity region 8 and the junction area between the p-type impurity region 8 and the n-type impurity region 9 are different from those in the related art where the junction surfaces 4a and 5a are linear. And the resistance of the protection diodes 4 and 5 is reduced. Therefore, when a surge voltage is applied to the gate electrodes 1 and 2, the surge current flows efficiently to the source electrode 3 through the low-resistance protection diodes 4 and 5.
The breakdown of the gate electrodes 1 and 2 is avoided, and the function of the MES type compound semiconductor device is ensured.

Further, in the above embodiment, a dual gate type semiconductor device has been described as an example, but the present invention is not limited to this and can be applied to a single gate type. Further, in the above embodiment, between the gate electrode and the source electrode
Although the protection diode is formed by the impurity region of the npn structure, the protection diode can be formed by the impurity region of the pnp structure.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part of a semiconductor device according to an embodiment of the present invention, FIG. 2 is a configuration diagram of an OR circuit having a protection diode, and FIGS. FIG. 1 is a plan view of a semiconductor device provided with a protection diode of FIG. 1, 2, ... gate electrode, 3 ... source electrode, 4, 5, ...
Protective diodes, 4a, 5a... Junction surface, 7, 9... N-type impurity region, 8.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01L 27/088 H01L 27/08 102F 29/41 29/812

Claims (1)

(57) [Scope of request for utility model registration] 1. Two pns between a gate electrode and a source electrode.
Type protection diodes are provided in series with their directions reversed,
The two junction surfaces formed by the n-type impurity region and the p-type impurity region of the protection diode have a waveform shape, and the junction length in a direction orthogonal to the direction of the diode is substantially the same. MES type compound semiconductor device.