JP3207957B2 - Method for forming InSb thin film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an InSb thin film used in a method for manufacturing a Hall element.

[0002]

2. Description of the Related Art Magnetoelectric conversion elements, particularly Hall elements, are small and highly reliable, and have been widely applied to various uses such as replacements for brushes of video and audio motors and rotation sensors for automobiles. This Hall element is made of GaAs or In.
The method uses a material of Sb. If the active layer is GaAs, it is formed by ion implantation, and if the active layer is InSb, it is formed by vacuum deposition. The former is used in fields such as automobiles where the forbidden bandwidth is large and excellent in temperature characteristics, and the temperature characteristics are important, while the latter is used in fields where electron mobility is large and excellent in magnetic sensitivity and power consumption is important. Can be

As shown in FIG. 4, a conventional method for forming an InSb thin film employs a method of forming In and Sb on an insulating substrate 41 such as mica.
From each deposition source at an ambient temperature near the melting point of InSb to form an InSb thin film 42, form an electrode 43,
Mold on plastic package.

[0004]

When InSb, which is a binary compound of In and Sb, is formed by vacuum deposition only,
Because of the high vapor pressure, control of the ambient vacuum was required.
Further, in order to form an n-type active layer, strict control of the deposition rate of In and Sb is required, and the production was performed under extremely controlled conditions (for example, the control of the degree of vacuum was disclosed in Japanese Patent Application No. 2006-163873). JP-A-56-177394; control of the evaporation rate is disclosed in Japanese Patent Application No. 56-50294.

In the prior art, low-temperature deposition causes poor crystallinity, and heat treatment after low-temperature deposition removes Sb, making it difficult to control the composition. Therefore, high-temperature deposition must be performed. In addition, since high-temperature deposition is performed, the active layer must be formed by vapor deposition over the entire surface of the material to be vapor-deposited, and thereafter, there is a problem in that the offset voltage increases due to variations in etching.

Further, the orientation of mica crystals is important for a deposition substrate, and a film cannot be successfully formed on SiO ₂ (glass). Furthermore, on a conventional material such as mica, a differential amplifier or a Schmitt circuit cannot be formed in a planar structure, and a monolithic IC cannot be formed. An object of the present invention is to provide a stable InS
An object of the present invention is to provide an InSb thin film forming method capable of easily obtaining a b thin film.

[0007]

[0008]

InSb thin film forming method of the present invention According to an aspect of the, 0.1 [mu] m or more 2μm following the Si substrate surface
After forming the irregularities, an insulating film is formed on the surface of the Si substrate.
Forming an InSb thin film on the insulating film by vapor deposition;
It is characterized by the following. At this time, wet etching or
Forming irregularities on the Si substrate surface by dry etching
Is preferred.

[0009]

[0010]

[0011]

According to the method of forming an InSb thin film of the present invention , Si
Since unevenness corresponding to the unevenness of the substrate remains on the insulating film surface,
The protrusions can disperse the bonds between In during vapor deposition,
As a result, the bonding between In and Sb is promoted, and
Therefore, In and Sb can be easily and stably deposited on the Si substrate .

[0012]

[0013]

FIG. 1 is a sectional view of a Hall element formed by a method of forming an InSb thin film according to one embodiment of the present invention. After forming irregularities on the Si substrate 1 by polishing finish of about 1.3 microns irregularities or wet etching or dry etching, SiO ₂ or plasma Si is formed.
₃ to form an insulating film 2 of N ₄ or the like, In and Sb thereon
Is deposited from each deposition source to form the InSb thin film 3. Unevenness corresponding to the unevenness of the Si substrate 1 remains on the surface of the insulating film 2, and the uneven surface of the insulating film 2 has InS
The b thin film 3 is formed.

At this time, the deposition temperature can be any temperature in a wide range from room temperature to around the melting point. After evaporation, SiO
_A heat treatment protective film 5 is formed on the surface of a material deposited from In and Sb deposition sources with ₂ or plasma Si ₃ N ₄ . After forming the heat treatment protection film 5, heat treatment is performed.
This heat treatment is a heat treatment in two or more temperature ranges.
After forming the Hall element after the heat treatment, the Si
The differential amplifier and Schmitt circuit formed on the substrate are connected with wiring metal and molded into a package.

In an experiment, when vapor deposition was performed on a Si substrate having no irregularities, only crystallization of In proceeded and stable InSb could not be formed. This means that irregularities of about 1 micron disperse the bonding between In during the deposition and cause In and Sb
It is thought to promote the binding of The size of the irregularities is preferably 0.1 μm or more and 2 μm or less.

After the vapor deposition, when heat treatment is performed to promote the bonding between In and Sb, the vapor pressure of Sb is high and Sb has a high vapor pressure at atmospheric pressure as shown in FIG.
As shown in the figure, Sb on the surface evaporates. Therefore, SiO
₂ and plasma Si ₃ N ₄ are formed as a protective film on the surface of the material deposited from the respective sources of In and Sb, thereby preventing Sb from evaporating during the heat treatment, as shown in FIG. .

It can be seen from FIG. 3 that a high mobility can be obtained by heat treatment in two or more temperature ranges. In FIG. 3, a curve A indicates a heat treatment temperature of 420 ° C.
Shows the electron mobility when only one stage is used, and curve B
Indicates the mobility of electrons when the heat treatment temperature is set at two stages of 300 ° C. and 420 ° C. It is presumed that high mobility can be obtained by two or more stages of heat treatment because damage during vapor deposition is recovered in the first stage and the bonding between In and Sb is promoted in the second and subsequent stages.

According to the above-mentioned forming method, it is possible to obtain a film quality having a high mobility of 20,000 cm ² / V · sec at room temperature. In addition, even though the heat treatment in one stage is slightly inferior to the heat treatment in two or more stages, necessary characteristics can be obtained. Thereafter, an electrode 4 is formed, and a protective film 6 is further formed thereon.

According to the above-mentioned method, the ambient temperature at the time of vapor deposition can be set widely from room temperature to the melting point. At the time of vapor deposition, desired patterning is performed, and In and Sb are respectively deposited in the patterned regions. After evaporation from the evaporation source, after forming a desired active layer by lift-off after evaporation,
A manufacturing method for performing heat treatment can be easily performed. According to this method, an offset voltage due to uneven etching can be suppressed.

Further, the deposited film thus formed can be easily connected to a differential amplifier or a Schmitt circuit formed on a Si substrate in the same wafer by a wiring metal and has a high sensitivity.
C can be commercialized.

[0021]

As described above, according to the InSb thin film forming method of the present invention , irregularities corresponding to the irregularities of the Si substrate are completely eliminated.
Since it remains on the surface of the edge film, unevenness may cause bonding between In during vapor deposition.
Can be dispersed, so that the bonding between In and Sb is promoted.
Will proceed to the fact, therefore, stable on Si substrate
Forming a thin film of I NSB is possible, it is possible to supply an inexpensive product of high yield. In addition, integration becomes possible,
A multifunctional device is realized, which can contribute to downsizing of the set.

[Brief description of the drawings]

FIG. 1 is a sectional view of a Hall element formed by an InSb thin film forming method of the present invention.

FIG. 2 is a distribution diagram of In and Sb in a depth direction of a deposited film formed by the method of forming an InSb thin film of the present invention.

FIG. 3 is a diagram showing the influence of the heat treatment of the deposited film on the mobility by the InSb thin film forming method of the present invention.

FIG. 4 is a cross-sectional view of a Hall element formed by a conventional InSb thin film forming method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Si substrate 2 Insulating film 3 InSb thin film 4 Electrode 5 Heat treatment protective film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI H01L 43/08 H01L 43/08 S 43/12 43/12 (72) Inventor Katsushi Tara 1006 Kadoma Kadoma, Kadoma City, Osaka Matsushita Electric (72) Inventor: Motoyoshi Yoshimoto, 1006 Kadoma, Kazuma, Osaka Pref. Matsushita Electronics Corporation (56) References JP-A-59-46077 (JP, A) JP-A-49-69074 ( JP, A) JP-A-49-107187 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 43/14 C23C 14/14 H01F 10/08 H01F 10/26 H01L 43 / 06 H01L 43/08 H01L 43/12 JICST file (JOIS)

Claims (2)

(57) [Claims] 1. The method according to claim 1, wherein the surface of the Si substrate has a thickness of 0.1 μm or more and
After forming the lower irregularities, an insulating film is formed on the surface of the Si substrate.
And forming an InSb thin film on the insulating film by vapor deposition.
A method for forming an InSb thin film, comprising: 2. A wet etching or a dry etching.
Forming irregularities on the Si substrate surface by
The method for forming an InSb thin film according to claim 1 .