JPS6236304Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a semiconductor device in which a plurality of different transistor element portions of direct current amplifiers are formed within one semiconductor pellet.

The DC current amplification factor h _FE of a transistor is required to have various values depending on the purpose of the transistor _.
Formed multiple transistor element parts with different _FE
Semiconductor devices such as IC devices are commercially available.
Individually manufactured transistors are manufactured from a single semiconductor wafer with multiple units of the same _hFE , and there is no manufacturing problem, but semiconductor pellets having multiple transistor element parts with different _hFEs The following problems arose in the production of

That is, when forming a plurality of transistor element parts with different h _FE in one semiconductor pellet, h _FE
Conventionally, this has been done by selecting the impurity concentration of the emitter region in each transistor element section. Therefore, for example, to form three different types of _hFE transistor element parts in one semiconductor pellet, the impurity diffusion process for forming the emitter region, the PR process associated with this process, the masking process, etc. must be performed at least three times. As a result of this necessity, the number of manufacturing steps was significantly increased, resulting in problems such as not only high costs but also a high incidence of defective products.

The present invention has been devised in view of such problems, and provides a semiconductor device in which a plurality of transistor element portions having different h _FE by changing the area pattern of emitter electrodes are formed in one semiconductor pellet.

As a result of various experiments, the present inventor found that h _FE increases significantly when the emitter electrode of a transistor is formed by overlapping the emitter-base junction. This invention is based on this knowledge,
The size of the emitter electrode in multiple transistor element parts formed in one semiconductor pellet is
The _hFE of each transistor element part is set to a different desired value by changing the overlap ratio of the emitter-base junction in the transistor element part.

Hereinafter, the present invention will be explained in detail with reference to the embodiment shown in FIG.

In FIG. 1, 1 indicates semiconductor pellets 2, 3,
Reference numeral 4 designates a plurality of transistor element portions, for example, three transistor element portions, each having a different _hFE , formed on the semiconductor pellet 1. These transistor element portions 2, 3, 4 are formed by selectively diffusing N-type base regions 5, 5', 5'' from the surface side of the P-type semiconductor pellet 1, and further forming base junction portions 5, 5', 5''. P-type emitter regions 6, 6',
An example of a vertical type PNP transistor structure formed by selectively diffusing 6" is shown.7
8 is an oxide film (insulating film) selectively deposited on the surface of each transistor element portion 2, 3, 4;
9 and 10 are base electrodes formed on the exposed surfaces of the base regions 5, 5', and 5'' of each transistor element section 2, 3, and 4; The emitter electrodes, which are a feature of the present invention, are formed on the exposed surfaces of the emitter regions 6, 6', 6'', and the base electrodes 8, 9, 10 and the emitter electrodes 11, 12, 13 are formed by metal vapor deposition such as aluminum. are formed all at once. 14 is a common collector electrode formed on the back surface of the semiconductor pellet 1.

The base regions 5, 5', 5'' and emitter regions 6,
The size and impurity concentration of the base regions 5, 5', 5" and the emitter regions 6, 6', 6" may be the same. Therefore, the manufacturing process such as the diffusion process for forming the base regions 5, 5', 5" and the emitter regions 6, 6', 6" is required for one sheet. This process is the same as the process of forming a plurality of same transistor elements of _hFE from a semiconductor wafer, and only requires a small number of steps.
The sizes of the emitter electrodes 9 and 10 may all be the same, and only the sizes of the emitter electrodes 11, 12, and 13 are different.

For example, the emitter electrode 11 in the transistor element section 2 at the left end of FIG.
The base joint portion 15 is set to a size that does not overlap. The emitter electrode 12 in the transistor element part 3 in the center of FIG.
As shown in FIG. The emitter electrode 13 in the transistor element section 4 at the right end in FIG. 1 is connected to the emitter-base junction 1 of the same transistor element section 4.
5'' is set to a size that overlaps all around the circumference as shown in C of FIG. It is formed all at once through one PR process, one masking process, etc., and this manufacturing process is the same as conventional transistor electrode formation and requires fewer steps.

h _FE of the transistor element section 2 at the left end of Fig. 1
is set to be 100, the transistor element section 4 at the right end of FIG.
3 overlaps, so the h _FE of this increases to about 200. In other words, on the surface of the emitter-base junction 15'', the emitter current is likely to disappear due to recombination based on the surface state due to sodium ions in the oxide film 7, but on the surface of the emitter-base junction 15'', When the emitter electrode 13 overlaps a portion, an electric field effect occurs in the overlapped portion.
The current flowing through the surface decreases, resulting in an increase in _hFE . Furthermore, h _FE of the central transistor element section 3
100 of the first leftmost transistor element section 2 and the first
Take an intermediate value between 200 and 200 of the transistor element section 3 at the right end of the figure, and for example, as shown in the figure, the emitter electrode 1
2 overlaps the emitter-base junction 15' by about half, h _FE of the transistor element portion 2 becomes about 150. 100, 150, 200 of such transistor element parts 2, 3, 4
_hFE was confirmed as experimental data.

Although the above embodiment has been explained using a vertical type PNP transistor, the present invention can also be applied to a lateral type transistor using the same principle as above.
The same applies to NPN transistors.

As explained above, the present invention forms a plurality of transistor element parts with different h _FE in one semiconductor pellet by simply changing the size of the emitter electrode. It can be performed in the same process as that used for manufacturing standardized transistors, and can significantly reduce the number of steps, improving yields and reducing costs. Furthermore, h _FE can be changed arbitrarily simply by changing the mask used during electrode formation.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
This figure is a schematic partial plan view showing the relationship between the emitter electrode and the emitter-base junction in each transistor element section of FIG. 1. 1... Semiconductor pellet, 2, 3, 4... Transistor element portion, 11, 12, 13... Emitter electrode, 15, 15', 15''... Emitter-base junction.

Claims (1)

[Scope of utility model registration request] A plurality of transistor element parts are formed in one semiconductor pellet, and the size of the emitter electrode in each transistor element part can be selected by selecting whether the emitter-base junction on the surface does not overlap or the proportion of overlap. A semiconductor device characterized by changing the DC current amplification factor into multiple stages.