JPH0658977B2 - Semiconductor element - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel semiconductor device. More specifically, it is intended to provide a novel semiconductor element having a wide band gap (forbidden band width) and suitable as a light-emitting base that emits light having a short wavelength (high energy).

2. Description of the Related Art In recent years, solid-state light emitting devices such as LEDs, ELs, and semiconductor lasers have been widely used in various OA devices. However, the fact is that the one that emits light of short wavelength (blue) has not been developed yet.

This is because a dopant (acceptor or donor) is appropriately added to a material having a sufficiently wide bandgap as a light-emitting matrix for emitting blue light (short wavelength = high energy).
This is because valence electron control (pn control) for arbitrarily forming a p-type or n-type semiconductor is not performed.

ZnS, ZnSe, ZnTe, CdS, CdSe, Cd
Te or ZnS _1-x Se _x , ZnSe _1-y Te _y , Zn
II-VI group compound semiconductors such as Cd _{1 -z} Te _z are often direct transition type and have a wide band gap, and are materials for light emitting devices in the wavelength range from visible light (blue) near the short wavelength to near ultraviolet. Has good qualities as.

However, most of the II-VI group compounds cannot perform pn control by adding impurities because of the self-compensation effect.
Only II-VI group compounds other than CdTe can form either p-type or n-type semiconductors, and it is extremely difficult to form both p-type and n-type semiconductors.

Above all, there has not been reported yet an example in which pn control is possible in ZnSe, ZnSSe, and ZnTe, which have a wide band gap and are expected as a blue light emitting matrix.

Further, in order to realize the pn control, first, it is necessary to form a good crystal with good lattice matching and no impurities.
It is difficult to produce good crystals as described above by the CVD method or the LPE method, which is a conventional crystal growth technique in the thermal equilibrium state. Therefore, MBE method, ALE method, HWE method, MOCV, which is a crystal growth method in a non-thermal equilibrium state.
Although the D method and the like have been studied, sufficient results have not been obtained yet.

Therefore, the present invention takes advantage of the fact that the energy level of the quantum well is significantly increased in the superlattice structure, and thus II-VI having a wide band gap capable of emitting blue light.
It enables pn control using a group compound semiconductor, and thus is suitable as a light-emitting matrix that emits light of short wavelength (high energy) (blue light) having a wide band gap (forbidden band width). It is an object to provide a new semiconductor device.

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the semiconductor device of the present invention comprises:
The first is zinc telluride (Z
nTe) semiconductor ultrathin film and intrinsic zinc zinc selenide (Z
pn composed of a p-type semiconductor having a superlattice structure in which a large number of semiconductor ultrathin films of nS _1-x Se _x ) are alternately laminated and a semiconductor of n-type zinc sulfuride selenide (ZnS _1-x Se _x ). The second one is characterized by having a junction, and the second one is a semiconductor ultrathin film of zinc selenide (ZnSe) and an intrinsic zinc zinc selenide (ZnS _1-x Se _x ) which is easy to form an n-type one. An n-type semiconductor having a superlattice structure formed by alternately stacking a large number of layers and zinc telluride (ZnT) that is easy to form a p-type
e) Semiconductor ultra-thin film and intrinsic zinc zinc selenide (ZnS)
It is characterized by having a pn junction composed of a p-type semiconductor having a superlattice structure in which a large number of _1-x Se _x ) semiconductor ultrathin films are alternately laminated.

Examples Details of the semiconductor device of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a diagram showing the distribution of energy levels of an example of the semiconductor device of the present invention.

This semiconductor is a p-type zinc telluride (ZnTe) semiconductor ultrathin film added with antimony (Sb) as an acceptor and an intrinsic zinc zinc selenide (ZnS _1-x Se _x , hereinafter referred to as ZnSSe) semiconductor ultrathin film. A large number of and are stacked to form a superlattice structure semiconductor.

With such a superlattice structure, the band gap is 2.
The band gap on the valence band side of 26 eV p-type ZnTe is greatly expanded due to strain of the lattice constant and the quantum well effect, and finally, the band gap of 3.15 eV of ZnSSe is wide without being damaged. The band gap is retained.

Furthermore, since a considerable part of holes existing in p-type ZnTe (ZnTe) has a small film thickness of ZnTe and ZnSSe,
To keep the tunnel effect or statistical mechanical equilibrium, Zn
The phenomenon of moving to the SSe side occurs, which causes ZnS
Se becomes p-type, and therefore this p-type ZnTe / ZnS
The Se superlattice structure semiconductor forms a p-type semiconductor while maintaining a bandgap that is almost the same as that of ZnSSe.

Next, the physical characteristics of a semiconductor element having a ZnTe-ZnSe superlattice structure will be described as an example.

Tables 1 and 2 on the next page show the characteristics of ZnTe and ZnSe single films.

FIG. 3 shows an example of photon energy-emission intensity characteristics of a ZnTe film having Li ₃ P as a dopant as in Sample 1 in Table 1.

Table 3 on the next page shows various amounts of semiconductors having a ZnTe-ZnSe superlattice structure.

FIG. 4 shows an example of photon energy-emission intensity characteristics of a semiconductor having a ZnTe—ZnSe superlattice structure in which Li ₃ P is used as a dopant as in Sample 6 in Table 3.

It can be seen that the peak portion indicated by “Ex” has moved to the high energy side as compared with FIG. 3 above. This is a characteristic that cannot be expected from a simple combination of materials.

In addition, H ₂ is further used in Sample 7 in Table 3,
In this case, high concentration P-type ZnTe-ZnS of the order of 10 ¹⁷
e Superlattice is obtained.

The electrical characteristics of the Li ₃ P-doped ZnTe—ZnSe superlattice are shown in Table 4 on the next page.

Table 4 shows two examples of different layer thickness and number of layers.
“Eg” indicates the energy gap, “P” indicates the carrier concentration, “μ” indicates the mobility, and “ρ” indicates the resistivity. Those marked with "*" are calculated values.

P using Li ₃ P shown in Sample 1 of Table 1 as a dopant
The difference becomes clear when it is compared with the mobility and the resistivity of the type ZnTe film.

In the present invention, P-type ZnTe obtained by adding N using NH ₃ is used.
-ZnSe superlattice can be mentioned as an embodiment,
An example of wavelength-emission intensity characteristics is shown in FIG. 5 (for the N-doped ZnTe film, see Sample 3).

FIG. 2 is an energy level diagram when an n-type ZnSSe semiconductor in which a donor such as bromine (Br) is added is joined to the above-described p-type ZnTe / ZnSSe superlattice structure semiconductor. , A pn junction having a wide bandgap is obtained, and an injection type E emitting blue light is obtained.
L makes it possible to manufacture a semiconductor laser.

The same thing as above can be said when the n-type superlattice structure semiconductor is made from the n-type ZnSSe semiconductor ultrathin film and the intrinsic ZnTe semiconductor ultrathin film. If a pn junction is made of a superlattice semiconductor of / ZnTe and a p-type ZnTe semiconductor, an injection type EL emitting from red to green emission color becomes possible.

The semiconductor device of the present invention is manufactured by H. W. E. Method (hot wall epitaxy method).

FIG. 6 shows H.264. W. E. 1 schematically shows the configuration of the device, the source tube and the heater tube are made of quartz glass,
A molybdenum wire is used as the heater wire.

The growth yarn is composed of a head portion, a wall, a source portion, and a reservoir portion, and these are temperature-measured by using a thermoelectric lamp of chromel-alumel, and each temperature can be controlled independently by a temperature controller.

The substrate is placed on the head portion and is configured so that it can be heated by a heater from the back side thereof. The head is slid by a stepping motor (not shown),
Superlattice growth can be realized by reciprocating the substrate in the chamber.

FIG. 6 shows a configuration example of an apparatus for growing a P-type N-doped ZnTe—ZnSe superlattice. One source source ZnTe is put in the reservoir part and the other source source ZnSe is put in another source part. Ammonia (NH ₃ ) gas is directly drawn into the ZnTe source through the quartz tube.

In that case, the partial pressure of the ammonia gas is 1 × 10 ⁻⁵ To.
It is kept at rr. And the temperature of each part is as illustrated.

In this example, it is preferable that ZnTe is put in the reservoir portion to grow by heating. This is because if ZnTe is put in the source part, it is difficult to control the growth rate if the source part is kept at a high temperature in order to decompose the ammonia gas.

EFFECTS OF THE INVENTION As is apparent from the above description, the first semiconductor device of the present invention is the semiconductor ultrathin film of zinc telluride (ZnTe) and the intrinsic zinc zinc selenide (ZnS _{1 -x} Se _x ) semiconductor ultra-thin films are alternately laminated to form a superlattice structure of a p-type semiconductor and an n-type zinc sulfuride selenide (ZnS _1-x Se _x ). The second one is characterized in that it has a semiconductor ultrathin film of zinc selenide (ZnSe) and an intrinsic zinc zinc selenide (ZnS _1-x Se _x ), which are easy to form an n-type, alternately. An n-type semiconductor formed by stacking a large number of layers into a superlattice structure, a semiconductor ultra-thin film of zinc telluride (ZnTe) and an intrinsic zinc sulfuride selenide (ZnS _1-x Se _x ) that is easy to form a p-type semiconductor Stack many layers alternately It was composed of a p-type semiconductor comprising a superlattice structure p-
It is characterized by having an n-junction.

Therefore, according to the present invention, the band gap (forbidden band width)
It is possible to provide a novel semiconductor element that is suitable as a light-emitting base that emits light having a wide wavelength and a short wavelength (high energy).

[Brief description of drawings]

FIG. 1 is a diagram showing the distribution of energy levels in an example of the semiconductor device of the present invention, FIG. 2 is a diagram showing the distribution of energy levels of a pn junction semiconductor device according to the present invention, and FIGS. The figure shows the photon energy-emission intensity characteristics,
FIG. 6 shows H.264. W. E. It is a figure which shows roughly the structure of an apparatus (hot wall epitaxy apparatus).

Claims (2)

[Claims] 1. A zinc telluride (Zn telluride) which is easy to form a p-type one.
Te) semiconductor ultra-thin film and intrinsic zinc zinc selenide (Zn)
Pn composed of a p-type semiconductor having a superlattice structure formed by alternately laminating a plurality of semiconductor ultrathin films of S _1-x Se _x ) and a semiconductor of n-type zinc sulfuride selenide (ZnS _1-x Se _x ). Semiconductor device characterized by having a junction 2. Zinc selenide (Zn) which is easy to produce n-type
Se) ultra thin semiconductor film and intrinsic zinc zinc selenide (Zn)
An n-type semiconductor having a superlattice structure in which a large number of S _{1 -x} Se _x ) semiconductor ultrathin films are alternately stacked, and a zinc telluride (ZnTe) semiconductor ultrathin film and an intrinsic sulfur selenide that can easily form a p-type semiconductor A semiconductor device having a pn junction composed of a p-type semiconductor having a superlattice structure in which a large number of semiconductor ultrathin films of zinc (ZnS _1-x Se _x ) are alternately laminated.