JPS6037169A - MOSFET manufacturing method - Google Patents

Abstract

PURPOSE:To contrive to form an MOSFET to be formed on a substrate in a fine type, and to form a semiconductor device to be constructed by forming the MOSFET in a small type to be integrated by a method wherein after impurity ions and high melting point metal ions are implanted continuously to the surface part of the substrate using a gate electrode as a mask, heat treatment is performed to form source, drain regions, and at the same time, high melting point metal silicides are formed in this regions. CONSTITUTION:SiO2 films 7 are provided according to thermal oxidation, etc. on the side parts of a gate electrode 6 to protect the gate electrode 6. B ions are implanted using an SiO2 film 4 and the gate electrode 6 as masks in succession, and moreover high melting point metal ions, Mo ions for example, are implanted. Accordingly, B ions and Mo ions are implanted in the nearly same region in the substrate 1. Then the whole of the substrate 1 is heat-treated to form P type source, drain regions 8, 9 of shallow junction depths. At the same time, implanted Mo and Si constructing the substrate 1 are alloyed in the source, drain regions 8, 9 thereof to form Mo silicides, and sheet resistances of the source, drain regions 8, 9 are reduced extremely. After then, an interlayer insulating film 10 consisting of PSG, etc. is provided on the whole surface of the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION A) Industrial Application Field The present invention relates to a method for manufacturing a MOSFET provided on a semiconductor substrate.

(2) Prior art In recent years, in order to miniaturize MOSFETs formed on semiconductor substrates and simplify the process, a source and drain/region are formed in a self-aligned manner with respect to the gate electrode by ion implantation, and from this source and drain region. A method is adopted in which the source and drain electrodes are directly extracted using A/.

By the way, in the above method, in order to make the contact between the Al source and drain electrodes and the source and drain regions ohmic, it is necessary to reduce the sheet resistance of the source and drain regions. This was achieved by increasing the concentration.

However, when the impurity concentration of the source and drain regions is increased as described above, the source and drain regions are formed deeply during heat treatment for activation after ion implantation. For example, when boron B is implanted into an N-type semiconductor substrate to form P-type source and drain regions, the depth of the source and drain regions must be 0.5 mm or more in order to form a practical ohmic contact. I end up. For this reason, miniaturization of MOSFETs formed on a semiconductor substrate cannot be achieved, and this has hindered the high integration of branched semiconductor devices.

c) Purpose of the invention The present invention has been made in view of the above points, and
Miniaturization of MOSFETs formed on substrates and MOSFETs
The purpose of this invention is to achieve miniaturization and integration of a semiconductor device formed by forming an SFET.

2) Structure of the kite of the invention In the present invention, impurities and refractory metals are continuously ion-implanted into the surface of the substrate using the gate electrode as a mask, and then heat-treated to form source and drain regions. A structure is adopted in which high melting point metal silinide is formed within the region.

E) Embodiment FIGS. 1 to 8 are cross-sectional views showing the manufacturing method of the MO8FET of the present invention in order of steps, and the present invention will be explained in detail using these figures. First, -conductivity type, for example, an N-type semiconductor substrate (1
) on which a gate oxide film (2), a polycrystalline silicon layer (3),
5102 membranes (400λ, 5sooi, 1oo respectively)
A resist (5) in the shape of a gate electrode is formed in sequence with a film thickness of 0A (Fig. 2), and wet etching is performed using a mixed solution of hydrofluoric acid and ammonium fluoride using the resist (5) as a mask. Next, the 5i02 film (4) and the polycrystalline silicon layer (3) are etched, and the gate electrode (6) is etched.
After forming the resist, the resist (5 mm) is removed (FIG. 6).

Here, a 5i02 film (7) is provided on the side surface of the gate electrode (6) by thermal oxidation or the like to protect the gate electrode (6). Next, using the 5i02 film (4) and gate electrode [6] as a mask, 1
x1o/.

Boron B is ion-implanted (Fig. 4), and high-melting point metal such as molybdenum MO is ion-implanted at an energy of 150 KeV at 2×1015 to 1×1o/aA (Fig. 4).
Figure 5). As a result, B and MO are injected into approximately the same area within the substrate (1). Next, the entire substrate (1) is heated at a low temperature (
A heat treatment is performed for 30 minutes at a temperature of 60° to 70° C. to form shallow P-type source and drain regions (8) and (9) with a junction depth of 0.3 to 0.4° (FIG. 6). At the same time, in this source and drain region (8) (9J), the implanted Mo and St constituting the substrate (1) are alloyed to form MO silicide, and the sheet resistance of this source and drain region (8) (9J is It becomes very low.After that, PS is applied all over the board.
A contact hole a exposing the source and drain regions (8) (9J) is formed in an appropriate place with a gate oxide film (2J1 interlayer insulating film) on the source and drain regions (8) (9). Open a (Figure 7).Finally,
The source and drain electrodes α3 (I4) in contact with the source and drain regions (8) and (9) are formed in hp through these contact holes αIJtta to complete the MOSFET (Fig. 8).At this time, as described above, The source and drain regions (8) (93 have a low resistance due to molybdenum silicide, so the source and drain electrodes 13 (
14) and the source and drain regions (8) and (9), with good ohmic contact.

f) Effects of the Invention As described above, the method for manufacturing the MO8FET of the present invention involves sequentially ion-implanting impurities and high-melting point metal into the surface of the substrate using the gate electrode as a mask, and then heat-treating it. The source and drain regions contain silicide and are in good condition, so even if the junction is formed shallowly, the source and drain regions
By keeping the sheet resistance of the drain region low, ohmic contact can be made with the source and drain electrodes. Therefore,
It is possible to miniaturize MOSFETs formed on a semiconductor substrate, and as a result, it is possible to achieve high integration of semiconductor devices using MOSFETs.

[Brief explanation of the drawing]

1 to 8 are cross-sectional views showing the method of manufacturing MO8FET of the present invention in order of steps. (1)...Semiconductor substrate, (6)...Gate electrode, (8)
1 (9J...source, drain region, 113Q4)
...Source and drain electrodes.

Claims (1)

[Claims] 1) When forming a MOSFET on a semiconductor substrate, a gate oxide film is provided on the substrate, a gate electrode is formed on this gate oxide film, and then impurities and high melting point metals are applied to the surface of the substrate using the gate electrode as a mask. By continuous ion implantation and subsequent heat treatment, source and drain regions are provided in the semiconductor substrate, and at the same time, high melting point metal silicide is formed in the source and drain regions. A method for manufacturing a MOSFET in which source and drain electrodes are provided in contact with each other.