JPS6020955Y2 - semiconductor equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device, and particularly to a transistor structure in which an emitter region formed in a base region is ring-shaped.

A so-called ring emitter transistor, in which the emitter region of the transistor is formed in a ring shape, has been developed.

This type of transistor has a plurality of emitter regions shallower in depth than the base region and having an annular planar shape in a base region formed on a collector region, and these emitter regions are connected to each other. By integrating electrically equivalent transistor units in parallel, we are attempting to increase the power while preserving the high speed of the Souden Kaninit.

Although the transistor units are formed to be electrically approximately equivalent, they do not have completely equivalent characteristics.

Therefore, a stabilizing resistor is usually inserted between the emitter region and the emitter electrode of each unit to ensure uniform operation of each unit.

FIG. 1 is a partially cutaway perspective view of a conventional transistor unit.

In the figure, 1' is an N-type silicon semiconductor substrate and is a collector region.

2' is a P-type base region formed on the collector region 1', and 3' is an N+ type annular region formed in the base region 2'.
The emitter region of the mold, 4' is silicon dioxide (Sin2)
5' is a stabilizing resistor formed in an annular shape above the emitter region 3', and is made of an N-type polycrystalline silicon layer doped with impurities and having a predetermined resistance value. Emitter region 3 through window 6' drilled in 4'
’ is electrically connected to.

7' is silicon dioxide (S) deposited on the stabilizing resistor 5'.
8' is an emitter electrode deposited on the stabilizing resistor 5' and the insulating layer 7', and the emitter electrode 8' is connected to the emitter region 3' through the stabilizing resistor 5'.
is electrically connected to.

9' is a base electrode provided in the base region 2'.

The conventional transistor unit having the above-mentioned configuration has the disadvantage that the emitter-base junction capacitance on the side surface of the emitter region 3' is relatively large. In addition, in order to obtain a predetermined resistance value, the stabilizing resistor 5' It extends widely onto the base region 2'.

Therefore, an MO3 capacitance is generated between the emitter electrode and the base region, and together with the junction capacitance, these capacitances seriously impede the high frequency characteristics of the transistor unit.

The present invention aims to improve the above-mentioned conventional drawbacks, and its purpose is to reduce the capacitance between the emitter and base of each transistor unit in a transistor in which a plurality of ring-shaped emitter units are connected in parallel. It's about doing.

For that purpose, the present invention includes a semiconductor substrate having one conductivity type and acting as a collector region, on the surface thereof, a base region having a conductivity type opposite to that of the substrate, and a base region located inside the base region and extending from the region. In a transistor comprising an emitter region of the same conductivity type as the substrate, which has a shallow depth and an annular planar shape, and connects the emitter region and the emitter electrode with a stabilizing resistor, the inner side of the annular emitter region is A stabilizing resistor layer is laminated on the emitter region and the insulator, and an emitter electrode metal layer is laminated on the stabilizing resistor layer via the insulator to form the emitter electrode. It is characterized in that it is electrically connected to a metal layer, and will be described in more detail below with reference to examples.

FIG. 2 is a diagram illustrating an embodiment of the present invention, and is a partial cross-sectional view of the central portion of two transistor units among a plurality of transistor units formed on a silicon semiconductor substrate.

In the figure, 1 is an N-type silicon (Si) semiconductor substrate, which is a collector region.

Reference numeral 2 denotes a P-type base region formed on the collector region 1.

Inside the base region 2, an N+ type emitter region 3 having a depth shallower than the base region 2 and having an annular planar shape is provided.
is formed.

An insulator 4 made of silicon dioxide (SiO□) is formed inside the annular N+ type emitter region 3, and extends through the base region 2 to reach the collector region.

5 is a stabilizing resistance layer made of polycrystalline silicon deposited on the emitter region 3 and the insulator 4;

An insulating layer 6 made of silicon dioxide (Sin2) is applied onto the stabilizing resistance layer 5, and an emitter electrode 7 made of aluminum (A1) is applied onto the insulating layer 6.

The emitter electrode 7 is in ohmic contact with the stabilizing resistance layer 5 through a window 8 provided in the insulator layer 6.

Note that collector region 1, base region 2, emitter region 3
, an insulator 4, a stabilizing resistance layer 5, an insulator layer 6, and an emitter electrode 7 constitute a transistor unit U1.

Next to the transistor unit U1, there is a
Although not shown, a plurality of such transistor units are arranged in a matrix on the substrate constituting the collector region 1.

In addition, in FIG. 2, transistor units U□ and U
A base electrode 9 is provided between the electrodes 2 and 2.

In the transistor unit having the above configuration, the insulator 4 is provided inside the annular emitter region, so that the inside thereof is not in contact with the base region 2.

Further, since the stabilizing resistance layer 5 is provided only on the emitter region, no MO3 capacitance is formed between it and the base region 2.

Furthermore, since the insulating layer 6 is interposed between the emitter electrode 7 and the stabilizing resistance layer 5 in the portion other than the window 8, an MO3 capacitor is formed in this portion.

Therefore, for high frequency components, the MO3 capacitor is connected in parallel, so the input resistance is small and the input power loss is small.

On the other hand, since the DC component must flow only through the stabilizing resistor, the stabilizing effect against local current concentration remains unchanged.

In the above embodiment, the stabilizing resistance layer 5 is formed into an annular emitter region 3.
The stabilizing resistor layer 5 was deposited on the insulator 4 to have a circular planar shape, but the stabilizing resistor layer 5 was formed to form a stabilizing resistor layer radial in the 90° direction or 1200° direction with the window 8 as the center. You may.

Note that when forming the insulator 4 in the base region 2, so-called LOGO3 (Local Oxidation
It is preferable to form using the fSilican method.

Also, when forming the emitter region 3, after forming the insulator 4 in the base region 2 in advance by the LOCO3 method, doped polycrystalline silicon to be used as a stabilizing resistance layer is deposited, and the doped polycrystalline silicon is When the emitter region is formed by diffusing impurities into the base region, the stabilizing resistance layer and the emitter region are formed at the same time, which is advantageous in terms of process.

As described in detail above, in the present invention, since the insulator is provided inside the annularly formed emitter region, the junction capacitance on the inner surface of the emitter region is eliminated.

In addition, since the stabilizing resistance layer is not deposited on the base region as in the conventional case, the MO between the emitter and the base
3 There is almost no capacity.

As a result, the capacitance between the base and emitter is much smaller than that of the conventional type, resulting in significantly improved high-frequency characteristics.

In addition, in the present invention, an insulating layer is interposed between the emitter electrode and the stabilizing resistance layer, and an MO3 capacitance is formed between the emitter electrode and the stabilizing resistance layer, which becomes a bypass capacitance for high frequencies. input loss is reduced.

Furthermore, in the conventional structure, the base pull-out resistance Rbb'
Even if we reduce the width of the emitter region to reduce
Since the width of the stabilizing resistor needs to be a certain value, the MO3 capacitance between the emitter and base increases.

However, according to the present invention, the MO3 capacity does not increase and a predetermined stabilizing resistance value can be easily obtained.
Furthermore, the width of the emitter region can be made smaller, resulting in a smaller lateral base resistance directly under the emitter, so the emitter region can be reduced.
There is also the effect that the base bonding operates uniformly and the breakdown resistance is improved in both the forward and reverse directions.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway perspective view of a conventional transistor unit, and Figure 2 is a partially cut away perspective view of two transistor units formed on a silicon semiconductor substrate. FIG. In the figure, 1 is a collector region, 2 is a base region, 3 is an emitter region, 4 is an insulator, 5 is a stabilizing resistance layer, 6 is an insulator layer, 7 is an emitter electrode, 9 is a base electrode, Uo and U2
indicates a transistor unit.

Claims (1)

[Scope of utility model registration request] A base region having a conductivity type opposite to that of the substrate on the surface of a semiconductor substrate having one conductivity type and acting as a collector region, and a base region having a shallower depth than the region and having a planar shape inside the base region. In a semiconductor device comprising an annular emitter region of the same conductivity type as the substrate, and a stabilizing resistor connecting the emitter region and an emitter electrode, an insulator is formed to penetrate inside the annular emitter region. A stabilizing resistor layer is laminated on the insulator and the emitter region, and an emitter electrode metal layer is laminated on the stabilizing resistor layer with an insulator layer interposed therebetween. A semiconductor device characterized by electrically connecting a metal layer.