JPS5893324A - Semiconductive device - Google Patents

Abstract

PURPOSE:To eliminate aluminum corrosion and to secure long life as well as high reliability by a method wherein, after a contact window for connecting an electrode is formed, second CVD oxidation is performed so as to form the contact window again and then the aluminum electrode. CONSTITUTION:After a P type diffusion layer 2, an N<+> type diffusion layer 3, a gate oxide film 4 and a gate electrode 5 are formed in N type semiconductor substrate 1, a CVD oxide film 6 is formed to insulate the gate electrode 5 and a source electrode 9. Then a phosphate glass (PSG) layer 7 is formed on the film 6 to improve reliability and a contact window 8 for connecting the electrode is formed through the photolithographic technique. Thence a CVD oxide film 11 containing almost no impurities is formed, whereas the contact window 8 is again formed before the aluminum electrode is formed. As a result, phosphor within PSG begins to melt, thus preventing the aluminum corrosion due to water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to improving reliability in semiconductor devices.

As an example of a semiconductor device, an example of a field effect transistor is shown in FIG. In FIG. 1, a vertical field effect transistor is provided with a source and a gate electrode on one main surface and a drain electrode on the other main surface, and a P-type layer 2. N green mold layer 3. Gate oxide film 4 and gate electrode 5
An ICCVD oxide film 6 is formed to insulate gate electrode 5 and source electrode 9. Afterwards, to improve reliability, a CVD oxide film 6 was applied! J7ga')suCP8G
> layer is formed by POC/3 diffusion etc., and contact window 8 with the electrode is formed by photolithography technique. In the conventional structure in which the phosphorus glass (pso) layer 7 is formed under the aluminum source electrode 9, phosphorus in the PEG is leached out, promoting aluminum corrosion due to moisture, and causing the aluminum electrode to break.

The present invention has been made to eliminate these drawbacks.

A feature of the present invention is that in a semiconductor device, after forming a first CVD oxide film, a phosphorus glass layer (P2O) is formed, and after forming a contact (Ill) for connection with an electrode, a second CVD oxide film is formed. A semiconductor device is provided in which electrodes are formed after forming contact windows for connection with electrodes. That is, after forming the contact window, # of impurities is
A CVD film that does not contain any of the above components is formed, a contact window is formed again, and an aluminum electrode is then formed.The drawings will be described in detail below.

FIG. 2 shows an embodiment of the present invention, where 1 is an N-type substrate.

2 indicates a P-type diffusion layer formed within the N-type substrate 1. As shown in FIG.

3 is an N+ type scattering layer 4 formed in the P type diffusion layer 2 is a gate oxide film, 5 is a gate electrode, 6 is a CVD oxide film, 7 is a phosphorus glass (P2O) layer, and 8 is a contact with the electrode. window,
11 is after forming a CVD oxide film containing almost no impurities after the above formation, and after forming the contact window 8 again and forming a CVD oxide film 11.

An aluminum source electrode 9 is formed. Numeral 10 is a nine drain electrode 10 formed on the other main surface.

According to this structure, since there is a P2O film apart from the aluminum source electrode as in the conventional case, K does not promote aluminum corrosion as in the conventional case, so a highly reliable product with a long life can be obtained, which is highly effective.

Although the present invention has been described using a field effect transistor as an example, it is of course applicable to an ICsCs bipolar transistor.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a conventional field effect transistor. FIG. 2 shows structures according to embodiments of the present invention. In the drawings, l...N-type semiconductor substrate, 2
...P type region, 3...N+ type region 4
...Gate oxide film, 5...Gate electrode% 6,11...CVD oxide oxide film...
...Phosphorus glass (P2O) layer, 8...Contact window%9...Aluminum source electrode%lO.
...Drain electrode.

Claims (1)

[Claims] In a semiconductor device, a first CVD oxide film is formed on a substrate, and a phosphor glass layer (PE) is formed on the first CVD oxide film.
G) is formed to form a contact window for connection with the electrode, and a second CVD oxide film is formed to again form a contact 99 for connection to the electrode. A semiconductor device characterized in that: