JPS61100923A - Molecular beam source - Google Patents

Abstract

PURPOSE:To prevent the outbreak of the defect of an evaporated thin film and to make excellent the uniformity of a film thickness distribution, by making conical a hole bored in a cover-shaped plate provided around a jetting port of a crucible. CONSTITUTION:A hole 3 bored in a cover 2 provided in the end of a crucible 1 is shaped in a cone, so that the thickness of a plate in the part of the diameter D of the hole be zero. By reducing to zero an apparent thickness of the plate in relation to an actual thickness (t) of the plate of the cover, in this way, the spatial distribution of molecular beams in the molecular beam jetting port of the crucible 1 can be improved. Consequently, the defect of an evaporated thin film can be reduced, and also the uniformity of a film thickness distribution can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention aims to improve a molecular beam source used for emitting component elements from a crucible in the form of molecular beams and epitaxially growing them on a substrate.

[Background of the invention]

In order to prevent the flying of deposited particles due to spitting and bumping phenomena, which are considered to be one of the causes of defects in thin films produced by the MBE method, conventional methods have been used to prevent deposit particles from flying away due to spitting and bumping phenomena, which are considered to be one of the causes of defects in thin films produced by the MBE method. A Knudsen type crucible was used as shown in . That is, crucible 1
A lid with holes or a lid-like plate 2 was provided at the molecular beam outlet to prevent the deposit particles of the deposition sample 3 from directly flying out of the crucible 1. However, these lids have a plate thickness t, which narrows the spatial distribution of the molecular beam ejected from the hole diameter at the crucible ejection port. The relationship between the ratio of the hole diameter D (=2r) and the plate thickness t and the spatial distribution of the zero molecular line is as shown in FIG.

From the second rR, when the lid thickness 1=0, the spatial distribution has the best value of cosine θ in the angle θ direction.

As t increases, the spatial distribution narrows.

Good spatial distribution of the molecular beam at the crucible spout means good uniformity in the thickness distribution of the thin film deposited. That is, when vapor deposition is performed under the same conditions for the single molecule beam source and the vapor deposition substrate, the best film thickness distribution on the substrate is obtained when 1=0. The presence of the plate thickness t of the crucible lid used to prevent defects in the deposited thin film narrows the spatial distribution of the ejected molecular beams, causing the thickness distribution of the deposited thin film to deteriorate. There is.

[Purpose of the invention]

An object of the present invention is to provide a molecular beam source that prevents defects in thin films deposited by molecular beams and has good uniformity in film thickness distribution.

[Summary of the invention]

The molecular beam source of the present invention achieves the above object.

The hole provided in the lid-like plate installed near the crucible spout is shaped like a cone.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

An embodiment of the present invention is shown in FIG. 3(a), in which a hole 3 made in a lid 2 provided at the tip of a crucible 1 has a conical shape. That is, the plate thickness is set to 0 at the hole diameter portion. By setting the apparent plate thickness to 0 compared to the actual plate thickness t of the lid, the spatial distribution of one molecular beam at the molecular beam spout of crucible 1 can be improved, as explained in Fig. 2. (See Figure 3(b)).

Another embodiment of the present invention is shown in FIG. 4. The embodiment of FIG. 4 uses the lid of the embodiment of FIG. 3(a) upside down, and the same effect can be expected. .

Further, FIG. 5 shows a fifth embodiment showing still another embodiment of the present invention.
The illustrated embodiment has a plurality of holes in the lid 2,
By implementing the present invention on the lid of a crucible as in this example, it is possible to improve the spatial distribution of molecular beams at the crucible spout. Another effect is created that allows you to select things.

〔Effect of the invention〕

As described above, according to the present invention, by forming the hole in a conical shape, defects in the deposited thin film can be reduced, and the uniformity of the film thickness distribution can be improved.

[Brief explanation of drawings]

113th! I is a cross-sectional view of a crucible for explaining a conventional example, and Figure 2 is a diagram for explaining the relationship between the ratio of the plate thickness of the lid to the hole diameter and the spatial distribution of molecular beams at the crucible spout. 3(a) and (b) are a cross-sectional view of a crucible and a spatial distribution diagram of molecular beams for explaining the present invention in detail, and FIG. 4 is a cross-sectional view of a crucible according to another embodiment of the present invention. , FIG. 5 is a sectional view of a crucible according to yet another embodiment of the present invention. 1... Crucible, 2... Lid-shaped plate, 3... Vapor deposition sample. Sweep 2 Ro Hime 30 (b)

Claims (1)

[Claims] 1. A molecular beam source comprising a lid-like plate having a hole at a molecular beam outlet, wherein the hole is formed in a conical shape.