JPH03161937A - Manufacture of field-effect type transistor - Google Patents

Abstract

PURPOSE:To prepare an FET having an off-set type gate electrode in a self- alignment manner by directionally depositing an insulating film to a substrate with the exception of one side face of the gate electrode from an oblique direction and removing sections except an electrode side section in an anisotropic manner. CONSTITUTION:A first insulating film 3 is deposited directionally to a substrate surface 1, on which a gate electrode 2 is formed, with the exception of one side face of the electrode from an oblique direction, and the film 3 except a section deposited on the side face of the electrode 2 is removed in an anisotropic manner vertically to the substrate 1. A second insulating film 5 is deposited in a non directional manner, and taken off vertically in the anisotropic manner while leaving the sections of the side sections of the electrodes 2, thus preparing an FET having the off-set type gate electrode in a self-alignment manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a field effect transistor having an offset gate electrode.

[Conventional technology]

As a field effect transistor, M E S F E
T(Metal ScmecondueLor Fie
ld Er['cctTrans]stor) and M O
S F E T (Metal Oxide Scmc
conductor Field Efrcct Tr
Ansistor) etc. are known. These field effect transistors have a source region in which a source electrode is formed and a drain region in which a drain electrode is formed, and a gate electrode is formed in a channel layer located between the source region and the drain region. Among these, there is an offset gate type in which the gate electrode is offset from the center between the source region and the drain region toward the source region.

[Problem to be solved by the invention]

The electrode formed offset from the center between the source region and the drain region in this way has hitherto been of a non-self-aligned type. Furthermore, when forming a source region and a train region by implanting impurity ions into the semiconductor substrate using a gate electrode formed on a semiconductor substrate and its sidewalls as a mask, the sidewalls of the gate electrode are usually It was not possible to use an offset type gate electrode because the lengths of the side walls were equal.

Therefore, in view of the above-mentioned circumstances, the present invention has an eleventh object to provide a method for manufacturing a field effect transistor that can form a field effect type transistor in a self-aligned manner with an offset pattern. There is.

[Means to solve the problem]

In order to achieve the above-mentioned object, a field effect east type l according to the present invention is provided.
・The transistor manufacturing method includes a step of depositing a first insulating film directionally from a direction oblique to the substrate surface on which the gate electrode is formed, except for one side of the gate electrode; A process of firstly removing the first insulating film in an irregular manner perpendicular to the plate surface while leaving a portion deposited on the sides of the plate; The method is characterized by comprising a step of depositing the second insulating film, and a step of removing the second insulating film in a four-directional manner perpendicularly to the surface of the plate, leaving the deposited portion on the side of the gate electrode.

[Effect]

By doing this, r
z Side walls with different side wall lengths are formed.

[Length example]

Hereinafter, with reference to FIG. 1 regarding one row of long follicles of the present invention,
explain.

Figure 3 is a process diagram when the method for manufacturing a transistor of the W effect type 1 according to the present invention is applied to manufacturing a MESFET.

First, as shown in FIG. 5A, a pattern of the gate electrode 2 is directly formed on the surface of the semiconductor cutting board 1 by riff 1 off or the like. The cable 1 and the electrical base 2 are made of metal such as tungsten W, for example. Next, the first insulating film 3 is dried by an ECR-CVD method in which the directivity is shifted by 6 degrees in the deposition direction from the direction inclined with respect to the surface of the semiconductor substrate (see FIG. 3(b)). At this point, the first insulating film 3 is deposited directionally from the direction inclined to the surface of the overboard.
Do not deposit on one side that will be in the shadow of Gate 1 and Electrode 2.

Therefore, an insulating film 3 is formed on the surfaces of the semiconductor substrate 1 and the gate electrode 2 except for this portion. Note that the method for depositing the first insulating film 3 is not limited to the ECR-CVD method, but may be any deposition method that has directivity, such as a sputtering method.

Then, the first insulating film 3 is anisotropically removed in a direction perpendicular to the surface of the semiconductor substrate 1 by, for example, reactive ion etching (RIE). As a result, Figure 1 (
As shown in C), the first insulating film 3 is removed leaving only the portion deposited on the sides of the gate electrode 2.

Furthermore, as shown in FIG. 1(d), a second insulating film 5 is deposited non-directionally on the surface of the disordered plate.

In this case, the second insulating film 5 may be deposited by a bulk volume method with no directivity in the deposition direction, or the second insulating film 5 may be deposited from multiple directions by a deposition method with directivity in the deposition direction. It is also possible to cancel the directivity in the deposition direction by crucifying the particles. Then, in the same way that the first insulating film 3 is anisotropically removed from the direction perpendicular to the surface of the semiconductor substrate 1, the second insulating film 5 is removed by, for example, reactive ion etching (RIE) to remove the semiconductor substrate 1. L (removed anisotropically from the direction perpendicular to the surface of the plate 1. As a result, the first
As shown in Figure (e), the second insulating film 5 is connected to the gate electrode 2
is removed leaving only the part deposited on the sides.

By going through these steps, both sides of the gate electrode 2 have sidewall lengths L and L, as shown in FIG. 1(e).
The side walls where 2 are older brothers of each other are shaped 1 (L > L2). Therefore, if the source region and the drain region are formed by implanting impurity ions into the substrate surface using the gate electrode 2 having asymmetric sidewalls as a mask, the center between the source region and the drain region can be formed. A field effect transistor having a gate electrode formed at a position offset from the surface can be obtained in a self-aligned manner.

Incidentally, the above-mentioned failure example is M. Although the present invention is applied to the manufacture of an ESFET, the present invention can also be applied to the manufacture of a 6 MOSFET.

In that case, instead of forming the gate electrode 2 directly on the surface of the semiconductor substrate, an oxide insulating film or the like may be formed on the surface of the semiconductor substrate 1, and the keto electrode 2 may be formed thereon. .

〔Effect of the invention〕

As explained above, according to the present invention, the sidewall lengths of the sidewalls formed on both sides of the gate electrode can be nested with each other, thereby forming a field effect transistor with an offset structure in a self-contained manner. can do.

4. Simplification of drawings j. Fig. 1 shows the manufacturing process of a field effect transistor according to the present invention.
It is a construction district that has implemented a major example of the law.

DESCRIPTION OF SYMBOLS 1... Semiconductor planting board, 2... Gate electrode, 3... First insulating film, 5... Second insulating film.

Claims (1)

[Claims] A method for manufacturing a field effect transistor having an offset gate electrode, the method comprising: directionally extending one side of the gate electrode from a direction inclined with respect to a substrate surface on which the gate electrode is formed; depositing a first insulating film on the sides of the gate electrode, and depositing a first insulating film on the side of the gate electrode,
a step of anisotropically removing an insulating film perpendicular to the substrate surface; a step of depositing a second insulating film non-directionally with respect to the substrate surface; and a portion deposited on the side of the gate electrode. The second
A method for manufacturing a field effect transistor, comprising the step of anisotropically removing an insulating film perpendicular to the substrate surface.