JPS61280608A - Semiconductor device - Google Patents

Abstract

PURPOSE:To generate tunnel current in a super grid structural layer by providing specific super grid structural layer between a substrate and a ZnSe layer. CONSTITUTION:A semiconductor device is composed of the first layer 1 comprising the first semiconductor, a super grid structural layer 2 composed of multiple layers alternately laminating the first thin layers 3 comprising the first semiconductor laminated on the first layer 1 and the second thin layers 4 comprising the second semiconductor with different composition from that of the first semiconductor, and the second layer 5 comprising the second semiconductor laminated on the super grip structural layer 2. The super grid structural layer 2 containing the second thin layers 4 can generate tunnel current therein, making current voltage characteristics ohmic.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to a semiconductor device.

(b) Conventional technology Currently, GaA uAs (gallium aluminum arsenide), Z
Semiconductor single crystals, such as n5 (zinc sulfide) and ZnSe (zinc selenium), for which it is difficult to obtain a single crystal substrate, are formed on a single crystal substrate with similar lattice constants.

However, as shown in FIG.
7) Even if it were formed above, the difference in the energy gap between the two vehicle crystals caused the problem that the formed betarojunction (8) would act as a rectification barrier and its current-voltage characteristics would become non-ohmic as shown in Figure 5. .

Therefore, the Journal of Vacuum Science
Journal of Vac
uumScience and Technology
), 19(3) r 5ept, 10ct.

1981, P626-627, the band gap between the single crystal substrate and the semiconductor single crystal changes continuously, and the lattice constant of the single crystal substrate and the semiconductor single crystal changes. Generally, a method is adopted in which a grade layer having a similar value is arranged to obtain ohmic properties.

(C) The problem that the invention aims to solve is, for example, G.
When forming a Zn5e single crystal having approximately the same lattice constant as the substrate on an aAs (gallium arsenide) single crystal substrate, the above conventional method is used because the optimal single crystal for the above-mentioned grade layer has not yet been discovered. That is impossible.

(d) Means for Solving the Problems The present invention has been made in view of the above points, and its structural features include a first layer made of a first semiconductor, a layer laminated on the first layer and made of the first semiconductor. A superlattice structure layer formed by alternately stacking a plurality of first thin layers consisting of a first thin layer consisting of a second semiconductor having a composition different from the first semiconductor; The present invention includes a second layer made of a second semiconductor.

(E) Effect In such a configuration, a tunnel current flows in the superlattice structure layer.

Example) Figure 1 shows an example of the present invention.
00) plane, the substrate is a D-type GaAs single crystal substrate with 1
It has a carrier concentration of 018/aT+3.

(2) is a superlattice structure layer formed on the -main surface of the substrate (1), and the structure layer is made of non-doped or n-type GaAs single crystal with carrier concentration IQ 14~lQIS/c1113. The first thin layer (3) has a layer thickness of 10 to 20 people and a carrier concentration of 10"-1017/am'n
A second thin layer (4) of 10 to 20 layers made of type Zn5e single crystal is alternately laminated, for example, five layers at a time.

Furthermore, these thin layers (3) and (4) can be formed using, for example, MBE (molecular beam epitaxial) growth.

Specifically, the substrate (1) was placed in an ultra-high vacuum (10-''T).

Heat etching is performed at 630°C for 10 minutes. Thereafter, the above substrate 1) was maintained at a constant temperature of 400 to 450°C, and (i) Zn cell temperature was 300°C, Se cell temperature was 220°C.
A first step of forming a second thin layer (4) as (i)
It can be formed by alternately repeating the second step of forming the first thin layer (3) at a Ga cell temperature of 1020° C. and an As cell temperature of 220° C.

(5) is an n-type Z layer laminated on the superlattice structure layer (2).
n5e layer, the Zn5e layer is 1g16~1017
/cIT13.

FIG. 2 shows the band structure of the semiconductor device of this example.
Figure (a) shows the state when no voltage is applied, and Figure (b) shows the state when no voltage is applied.
The state is shown when a voltage is applied using 1) as the negative electrode and the 21136 layer (5) as the positive electrode. In FIG. 2, Ec and Ev are the conduction band and the valence band, respectively.

Moreover, FIG. 3 shows the tfIc voltage characteristics of an unexampled device.

As is clear from FIG. 3, the device of this embodiment exhibits ohmink. This is because the second thin layer (4) in the superlattice structure layer (2) is as thin as 10 to 20 people.
This is because a tunnel current is generated inside.

In this example, the first and second thin layers (3) of the superlattice structure layer (2)
)(4) was formed using the MBE growth method, but MOCV
It is also possible to form using other thin film growth methods such as D (organometallic vapor phase epitaxy) method and low temperature vapor phase epitaxy method. In addition, the superlattice structure layer (2) has a structure in which the first and second thin layers (3) and (4) are laminated alternately in sm, respectively, with the substrate (1) as the negative electrode and the Zn5e layer (5) as the positive electrode. When a voltage of several volts or less is applied, the conduction band of the Zn5e layer (5) changes to the substrate (1).
) The number of laminated layers may be any number as long as it is lower than that of ).

(G) Effects of the Invention By using the present invention, the lattice constant of a semiconductor single crystal for which a single crystal substrate is difficult to obtain is similar to that of such a semiconductor single crystal, and a band gear//
Even if it is formed on a semiconductor single crystal having a different energy, it is possible to make the current-voltage characteristics ohmic.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2(a) (
b) is a schematic diagram showing the band structure of the device of this embodiment, FIG. 3 is a characteristic diagram showing the current-voltage characteristics of the device of this embodiment, and 4I3
0 is a sectional view showing a conventional example, and FIG. 5 is a characteristic diagram showing current-voltage characteristics of the conventional example. (1)...Substrate (first opening, (2)...superlattice structure layer, (3)...-first thin layer, <4)...-second thin layer, (5)
・=ZnSe layer (second layer).

Claims (1)

[Claims] (1) A first layer made of a first semiconductor, a first thin layer laminated on the first layer and made of the first semiconductor, and a second thin layer made of a second semiconductor having a different composition from the first semiconductor. 1. A semiconductor device comprising: a superlattice structure layer formed by alternately laminating a plurality of layers; and a second layer laminated on the superlattice structure layer and made of the second semiconductor.