JP2936878B2 - Manufacturing method of semiconductor Schottky junction - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a Schottky junction formed by laminating a metal on GaAs and a method of manufacturing the same.

[0002]

2. Description of the Related Art A Schottky junction of GaAs is made of metal-
Semiconductor junction type electric field transistor-(MESFET), etc.
It is important as an element constituting a gate of an electronic device. The main performance index of the Schottky junction is Schottky barrier height,
SBH), and conventionally, SBH has been controlled by the type of metal to be laminated.

[0003]

A high SBH is desired to improve the operation characteristics of the above-mentioned transistor.
Since it is determined by the type of metal, there is a problem that the selection range of the metal type is limited.

It is an object of the present invention to achieve a high S
An object of the present invention is to provide a semiconductor Schottky junction realizing BH and a method for manufacturing the same.

[0005]

[0006]

In order to achieve the above object,
Therefore, the method for producing a semiconductor Schottky junction according to the present invention is a method for producing a semiconductor Schottky junction in which an intermediate layer is formed on a substrate, and then a metal is laminated. In the following, after using an As molecular beam and a Ga molecular beam and setting the As / Ga molecular beam flux ratio to be as small as possible within a range where the deposited film does not become amorphous, a GaAs layer is grown. This is a step of performing a heat treatment within a temperature range of ５550 ° C. without irradiating an As molecular beam.

[0007]

According to the present invention, an extremely thin G layer formed on GaAs is formed.
a due to the deep levels contained in the excess GaAs film
H is controlled.

A GaAs film having an excessive amount of Ga, that is, a film having a composition ratio (ratio of Ga to As atoms) of 1 or less, contains As
Many anti-site defects in which Ga is placed on the site are included. By fixing the surface potential to the deep level created by the Ga antisite defect, a high SBH independent of the metal species can be obtained. Since Ga antisite defects in GaAs create a level one electron volt (eV) below the conduction band, the formation of a Ga-rich GaAs intermediate layer on n-type GaAs results in a high level of about 1 eV. SB
H is obtained.

As a highly reliable method for producing a GaAs film containing excess Ga, a method described in claim 2 has been developed.
That is, when forming a structure by the MBE method, As / G
a The molecular beam flux ratio should be suppressed as much as possible for the production of the intermediate layer of the present invention. However, if the substrate temperature is high, Ga droplets are likely to be generated, and a flat surface cannot be obtained.
Keep below 50 ° C.

In this temperature range, if the As / Ga molecular beam flux ratio is too small, the film becomes amorphous. This amorphous GaAs is crystallized by a heat treatment in a later step, but is disadvantageous because it includes defects such as As vacancies that form shallow levels in addition to Ga antisite defects.

The As / Ga molecular beam flux ratio is set as small as possible within a range where the deposited film does not become amorphous, and the deposited film is heat-treated in the above temperature range.
GaAs mainly containing only Ga antisite defects is obtained.

[0012]

Embodiments of the present invention will be described below. Chemically etched Si-doped n (plus) (100) Ga
The As substrate was introduced into the MBE device. 1 × 10 ^-5 Torr
The substrate was heated to 630 ° C. while irradiating r As molecular beam, and the oxide film on the surface was evaporated. Continue G at 620 ° C
Irradiation was also performed by adding a and Si molecular beams to grow an n-type GaAs layer.

Thereafter, the substrate temperature was lowered to 200 ° C. while continuing the As molecular beam irradiation. Strength 1 × 10 ⁻⁶ Torr
The GaAs intermediate layer having a thickness of 2 nanometers (nm) is formed at a speed of 0.22 n by the As molecular beam reduced to r and the Ga molecular beam.
m / sec. This growth condition depends on the As / Ga flash
The ratio of 0.6.

Finally, all the molecular beams are stopped, and the sample is
Heat treatment was performed at 90 ° C. for 10 minutes. Gold and aluminum electrodes were formed on the sample taken out of the MBE apparatus by ordinary lithography, and a Schottky junction was formed.

The SBH determined from the current-voltage characteristics is 0.96 eV for gold and 0.94 eV for aluminum.
The values were higher than normal values (0.84 eV and 0.63 eV, respectively). When the GaAs intermediate layer growth rate is fixed at 0.22 nm / sec, the SBH of aluminum decreases to 0.54 eV when the As molecular beam intensity is as high as 1 × 10 ⁻⁵ Torr, and the film becomes amorphous 5 × 10 5 ^{Even at -7} Torr, it decreased to 0.84 eV.

[0016]

According to the present invention, a high SBH can be realized irrespective of the type of metal, and the degree of freedom in designing the device structure and process can be increased, and the device performance can be improved.

Claims (1)

(57) [Claims] 1. A method for producing a semiconductor Schottky junction in which an intermediate layer is formed on a substrate and then a metal is laminated, wherein the step of forming the intermediate layer comprises the steps of:
After growing a GaAs layer by using an s molecular beam and a Ga molecular beam and setting the As / Ga molecular beam flux ratio as small as possible within a range where the deposited film does not become amorphous, the sample is heated to about 450 to 550 ° C. Within the temperature range of
A method for producing a semiconductor Schottky junction, which is a step of performing a heat treatment without irradiating a molecular beam.