JPS58173830A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a stable contact region having low resistance by coating sections except the forming region of the contact region having stable ohmic contact resistance with an implantation mask and implanting boron ions into the contact region when the contact region is formed to a P type region layer. CONSTITUTION:The P type region layer 2 is formed to an N type Si substrate 1 through the diffusion of boron, and the whole surface containing the layer 2 is coated with an oxide film 3. A resist film 4 with openings corresponding to the contact regions formed to the region layer 2 is formed onto the region layer 2, openings are bored to the film 3 through a photoengraving method, and the contact regions 5 are exposed. Boron ions are implanted only into the regions 5, and the resistance of the region layer 2 positioned at the lower side of the regions 5 is lowered. Accordingly, the desired low-resistance contact regions are obtained in the region layer 2 only by implanting boron ions.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device in which a contact region having stable ohmic contact resistance is formed in a P shadow region layer.

Conventionally, ohmic contact to the P shadow region 1 is made by forming a P shadow region layer in an N type silicon layer, and using known photolithography to form part of the thermal oxide film formed at the same time or the oxide film formed by subsequent oxide film formation. The surface of the P shadow area is exposed by drilling a C hole using a technique, and then, for example, aluminum is deposited on the surface by a vapor deposition method or by a tuttering method to form an aluminum slope, and further by a known photolithography technique. Use C to form a line pattern within the predetermined range F4i1r',
Furthermore, after this, the P-type contact region layer and the internal wiring metal, such as aluminum ohmic contacts, are heat-treated to a temperature of 600"C at most.
Form.

Normally required P shadow area layer is 100Ω/mouth ~ 1000V
The surface concentration of the P-type impurity is 1X10''clls.To form a stable Oε2 contact, the P-type impurity surface concentration of 4X101'I:111 or more is desirable. When the surface concentration is lower than this, the variation in contact resistance value is large and the contact resistance value is unstable.

For this reason, in order to avoid instability of the contact resistance value, in the conventional P shadow region layer, when forming a low concentration region layer with few impurities, a high concentration region layer is used to increase the surface a degree. The disadvantage is that it requires special formation.

The present invention has been made to eliminate the drawbacks of the conventional devices as described above, and its object is to provide a semiconductor device 1d having a stable contact region with a low contact resistance value.

For example, in one example of the present invention, in order to form an ohmic contact to the P-type region layer using inner plate wiring, the P-type region other than the contact region is protected with an implantation mask, and the contact region is After implanting boron ions into the contact region, the inner plate wiring is subsequently formed, and heat treatment at 600°C or higher is not performed after the boron ion implantation into the contact region. form.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. In the figure, 'r, +1) is an N-type silicon layer, and (2) is a P-type region layer formed therein. The P-type region layer is formed by diffusing C, for example boron, using well-known photolithography and diffusion methods. The oxide film (3) is formed at °C by heat treatment to form a P-type layer or subsequent oxide film formation. After applying a resist (4) by photolithography, a contact region (6) is formed on the surface of the P-type region layer.

Alternatively, the resist (4) can be applied to the contact area +5) which has already been opened in the oxide film (3) by photolithography.
After coating the entire layer, only the necessary contact region (6) of the P-type region layer is exposed, and the contact of other N-type region layers or unnecessary P water high concentration surface impurity layer is covered with resist, and used as an ion implantation mask.

Subsequently, for example, 50% of C boron is added by ion implantation.
Drive 10”n at KeV.
U L/ Cyst (4> M!!3) has a thickness that prevents boron ions to be implanted from reaching areas other than the predetermined contact area, for example, if it is only the oxide film (3), it is about 0.5 μm,
Also, if there is no oxidation (1) (3), the resist (4) is l,
Set the thickness in advance to about #m and leave at °C.

After ion implantation, if the resist is used, it is removed at °C, the surface is cleaned, and without heat treatment, for example, aluminum is immediately applied by vapor deposition or sputtering, and a pattern is formed by photolithography. Thereafter, heat treatment is first performed at, for example, 460°C.

The surface of the P-type region layer manufactured by the above method can be easily contacted with the contact metal on the west side by ion implantation, and heat treatment after ion implantation can be performed even in the P shadow region with a low surface concentration. 400℃ after AlitA formation
By performing heat treatment at temperatures ranging from 450° C. to 450° C., a contact region exhibiting stable contact resistance can be formed.

Also, in the above embodiment, the wiring -? Although Lb4 was aluminum, the same effect can be obtained in the case of aluminum containing one or more types of aluminum, such as aluminum containing silicon or aluminum containing copper and silicon.

As described above, according to the present invention, a high fIIIf region layer is not required to form a contact region in a P-type low-# region layer, and boron ions are only implanted into a contact region in a P-type region. New heat treatment □There is a 51JJ effect that allows a contact region with stable contact resistance to be easily obtained without the need for treatment.

[Brief explanation of the drawing]

The drawing is a sectional view of a semiconductor device showing an embodiment of the present invention. In the figure, r fl) is N-type silicon 7F+, +2) is P
shape region layer, (3) is oxide film, (4) is resist, (5)
indicates the contact area, and the ↑ mark indicates the state where boron ion implantation is performed. +J Dear Commissioner of the License Agency 1, Indication of 1G Patent Application No. 1987-87698 2, Name of the invention Method for manufacturing a semiconductor device 3, Person making the amendment 6, @Detailed description of the invention in the original subject specification and column 6 of the brief explanation of the drawings, contents of amendment (1) “lXl0”am-” in line 8 of page 2 of the central cylinder of the specification.
J Toru no [lXl0-"cIll-"~lXl0
1.C11-"J&'ITCorrect-. (2) On page 8, line 9 of the same page, correct the phrase "because it will not be implemented," to read "it will not be implemented." (3) In the 8th line of page 6, the ``↑ mark'' should be corrected to ``↓ mark.''that's all

Claims (1)

[Claims] 1. A first method of manufacturing a semiconductor device, which comprises protecting the Pt1J1 layer other than the ohmic contact formation region with an implantation mask, implanting boron ions into the contact region to form a C contact region, and then forming internal wiring.