JPS5896762A - Semiconductor element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device, and particularly to a bipolar transistor with improved gain control and breakdown strength.

A conventional example of this type of bipolar transistor used for high frequency and high output is shown in FIG. That is,
In this FIG. 1, (1) is an n-type silicon substrate, (2
) is the first n-layer grown in vapor phase on this substrate, (3) is the first p-layer selectively formed on this first n-layer by diffusion or ion implantation, and (4 ) is this first
Similarly diffused onto the P layer.

or a second n layer selectively formed by ion implantation, etc.; (5) is an oxide film formed on these surfaces;
(6) and (7) are emitter and base electrodes made of gold or aluminum connected to the layers (4) and (3).
It constitutes a type bipolar transistor.

In such bipolar transistors for high frequency and high output, in order to obtain high gain and high output,
The formation depth of the first P layer (3) and the second N layer (4) is very shallow, which results in a structure that is extremely susceptible to destruction (due to uniform voltage excitation, excessive force excitation, abnormal load, etc.). As a countermeasure to this problem, conventionally, it has been necessary to add an automatic output control circuit, a so-called APC circuit, as an external circuit. However, since the power supply voltage of the drive stage is lowered in the APC circuit, troubles such as oscillation often occur.

In view of these conventional drawbacks, the present invention connects a field effect transistor to the emitter side of a bipolar transistor to improve its breakdown strength.

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 2 and 3.

FIG. 2 shows the structure of an NPN type bipolar transistor to which this embodiment is applied. In this Figure 2, the first
The same reference numerals as those in the figures represent the same or corresponding parts. In this embodiment, in the conventional example, the second PIF! t (8
) is formed, and an emitter electrode (
6), and a gate electrode (9) made of metal is provided via an oxide film (5).

An equivalent circuit of this embodiment is shown in FIG. 3. In the end, this embodiment has a structure in which a field effect transistor is connected to the emitter side of a bipolar transistor.

Therefore, according to the present invention, a field effect transistor is connected to the emitter side of a bipolar transistor, and since the field effect transistor is configured to be able to apply any voltage from the outside to its gate electrode, when excessive force excitation or overvoltage is applied, the applied voltage It has the advantage that it can protect the bipolar transistor from destruction by increasing the current and decreasing the emitter current, and that it can arbitrarily control the gain of the bipolar transistor by changing the voltage applied to the gate electrode.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the general structure of a conventional bipolar transistor, FIG. 2 is a sectional view showing the general structure of a bipolar transistor to which an embodiment of the present invention is applied, and FIG. 3 is an equivalent circuit of the structure shown in FIG. It is a diagram. (1)...n-type silicon substrate, C2)...first
(3)...first P layer, (4)...second n layer, (5)...oxide film, (6)...emitter electrode, (7)...Pace electrode, (8)...
Second P layer, (9)...gate electrode. Agent Makoto Kuzuno (1 other person) Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] forming a first n-type or p-type dielectric layer on a silicon substrate, and selecting mutually independent first and second p- or n-type dielectric layers for the first n- or p-type dielectric layer; and forming a 20th nt or P-type trench conductor layer on the first P or n-type trench conductor layer, and further forming a base electrode on the first P or n-type trench conductor layer and a second n- or P-type trench conductor layer and second
An emitter electrode connecting the second P- or n-type trench conductor layer, and a gate electrode provided on a part of the second P- or n-type trench conductor layer through an oxide film, respectively. semiconductor element.