JPH03200380A - Manufacture of znse light emitting element - Google Patents

Abstract

PURPOSE:To partly form a low resistance p-type ZnSe and to obtain a ZnSe light emitting element using the ZnSe by growing p-type ZnSe on a base while partly applying light to the base when flying containing materials from cells as molecular beams to grow the p-type ZnSe on the base. CONSTITUTION:When containing materials Zn, Se, P are flown from cells 3-5 as molecular beams to grow a p-type ZnSe on a base 2, the ZnSe is grown partly on the base 2 while applying laser light 9 thereto. Thus, when P-doped ZnSe is molecular beam epitaxially grown on the base 2 while the light 9 is applied, more P than the ZnSe grown on a non-irradiation part is input to the ZnSe grown on the irradiation part. That is, the specific resistance of the ZnSe of the irradiation part can be reduced by growing it while the light is partly applied on the base 2. Thus, partly low resistance p-type ZnSe can be formed, and a monolithic ZnSe element is obtained by using it.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to a method for manufacturing a ZnSe light emitting device.

(b) Conventional technology ZnSe (zinc selenium) compound semiconductor has approximately 2
．． Since it has a band gap of 7 eV, it is seen as a promising material for blue light emitting devices, but it has not yet been put to practical use. The reason for this is that in growth methods that use thermal equilibrium, such as the high-pressure melting method conventionally used to grow ZnSe single crystals, n-type and even p-type impurities remain during the growth because the crystal grows at high temperatures. It is incorporated as an impurity, making it difficult to obtain high-purity crystals. In addition, a self-compensating effect is brought about by the generation of endogenous defects due to vacancies caused by deviations from the stoichiometric ratio or composites containing vacancies, and only n-type crystals can be obtained after growth. There wasn't.

In addition, there is a report that p-type ZnSe can be formed by vapor pressure controlled temperature difference method (J, Appl, Phys, 59. (1
986) 2256-2258), but it is difficult to grow crystals with good reproducibility using this method, and even though this report has been published, it has not yet been put into practical use.

In recent years, chemical vapor deposition using organic compounds (MOCVD) and molecular beam epitaxial growth have been developed as low-temperature crystal growth methods that can minimize residual impurities during crystal growth and minimize the occurrence of self-compensation effects. (M
B E > is attracting attention.

In particular, by the MBE method, a highly pure undoped ZnSe single crystal having a resistivity of 104Ω or higher has been obtained. Furthermore, in the evaluation of its optical properties using low-temperature photoluminescence, the light emission from bound excitons, which indicates the contamination of impurities, and the light emission from deep levels due to defects, etc., are extremely weak. Products with excellent properties are obtained.

Furthermore, as disclosed in JP-A-62-79630, when 7 cubic centimeters of P is added at a cell temperature of 150 to 350°C during the growth of a ZnSe single crystal by the MBE method, deep A p-type ZnSe single crystal with good crystallinity that does not emit light from

Z formed by the method disclosed in JP-A No. 62-79630
In the nSe single crystal, it has been confirmed that light emission '(1'l) due to excitons bound to the acceptor level is obtained from the optical properties due to its low-temperature photoluminescence, and that the acceptor level is formed.

(c) Problems to be Solved by the Invention However, even if ZnSe crystals are grown using the BE method, there is a problem that residual impurities and the formation of donor levels due to self-compensation effects cannot be avoided. , p-type ZnSe prepared by the conventional method has a weak p-type property as a semiconductor because its 1゛1 emission intensity is equivalent to the emission (I,) due to excitons bound to the donor level, and it has a weak p-type property as a semiconductor. The resistance is also large and inconvenient, at 103-104Ω.

Therefore, by increasing the amount of P, which is an acceptor, l I
A possible method for increasing the emission intensity of , is to raise the temperature of the P cell to increase the P molecular beam intensity. However, this method is not preferable because it increases the amount of donor impurities that are contained in the P raw material and fly together with P.

Therefore, the present invention does not increase the temperature of the P cell,
By increasing the amount of P incorporated into the ZnSe single crystal, we can manufacture low-resistance p-type ZnSe and use this to produce Zn
The technical problem is to manufacture a Se light emitting device.

(d) Means for Solving the Problems The method for manufacturing a ZnSe light emitting device of the present invention involves preparing a Zn cell containing Zn, an Se cell containing Se, and a P cell containing P, and The method is characterized in that when p-type ZnSe is grown on a substrate by ejecting each contained material as a molecular beam from each cell, the growth is performed while partially irradiating light onto the substrate.

(E) Function According to the present invention, P-doped Z is applied while irradiating light onto the substrate.
When nSe is grown by MBE, Zn grows in the light irradiated area.
Se takes in more P than ZnSe, which grows in non-irradiated areas. That is, by performing growth while partially irradiating light onto the substrate, the specific resistance of ZnSe in the irradiated portion is reduced. Therefore, in a ZnSe light emitting device in which a p-type ZnSe layer is formed using such a method, current flows only through the low resistance portion of the p-type ZnSe layer, that is, the portion treated by light irradiation.

(f) Example FIG. 1 shows an example of an MBE apparatus used in the method of the present invention,
(1) is placed in the growth chamber, and (2) is placed in the growth chamber (1).
This is a p-type GaAs substrate having a 100) plane as its main surface. (3
) is a Zn cell that stores Zn, (4) is an Se cell that stores Se, (5) is a P cell that stores P, and (6) is a Ga cell.
Each of these cells is arranged in the growth chamber (1) to irradiate the substrate (2) with each material. Further, although not shown, each cell is provided with a shutter, so that each material can be irradiated onto the substrate (2) as desired. (7) is a translucent window provided on the wall of the reaction chamber (1) facing the substrate (2), and (8) is placed opposite the substrate (2) through the window (7). In a laser device such as an excimer laser or a He-Cd laser, the laser beam (
9) is condensed by a condensing lens (not shown), and the light is focused on the substrate (2).
irradiated on top.

Next, an example of a method for growing p-type znSe crystals using such an MBE apparatus will be described.

First, the degree of vacuum in the growth chamber (1) is set to 10-”
The substrate (2) was kept at 320°C and the Zn cell (3)
300℃, Se cell (4) at 200℃, P cell (5)
Heat to 300°C. Zn and S at such heating temperature
The molecular beam intensity ratio of e is 1. Next, while irradiating a portion of the substrate (2) with a laser beam (9), the shutter of each cell (not shown) is opened, and Zn, Se,
A P molecular beam is irradiated to grow a crystal of P-doped ZnSe.

In ZnSe formed by such a method.

The resistivity is different between the irradiated part and the non-irradiated part with the laser beam (9), and the resistivity of the non-irradiated part is 10", which is the same as in the conventional method.
Ω(1), while the specific resistance of the irradiated part is about I
Qcm. This is because the substrate (2) is locally heated in the area irradiated with the laser beam (9), so S has a high vapor pressure.
e is easily detached and becomes a substantial Z! This is based on the fact that the molecular beam intensity ratio of 1 and Se deviates, and the molecular beam intensity ratio of Zn increases. That is, as shown by the present inventors in Japanese Patent Application No. 63-202209, as the molecular beam intensity ratio of Zn increases, the amount of P incorporated into ZnSe increases.

FIG. 2 shows a monolithic ZnSe light-emitting diagonal array fabricated using the method of the present invention.

In the figure, (10) is an n-type GaAs substrate, (11) is an n-type ZnSe layer formed by irradiating Zn, Se, and Ga serving as a donor impurity onto the main surface of the substrate (10);
12) is a p-type Z formed by irradiating laser light from the direction of the arrow according to the above method only in the shaded area in the figure.
In the nSe layer, the shaded area is a low resistance area (12').

In this example, three locations are irradiated with laser light, but this may be done using a plurality of laser devices (8), or one laser device (8) may be used to scan each location ( 12°
) may be irradiated in sequence. (13) is each low resistance part (
(12°) is deposited on the Au electrode, (14) is the substrate (10
) is a Cr-5n-Au electrode deposited on the other main surface.

As a result, a ZnSe light emitting element array having a plurality of (three in this example) light emitting points is manufactured. Of course, the third
As shown in the figure, by irradiating laser light in a matrix, a display that displays dots can be realized.

Moreover, as shown in FIG. 4, p-type 2nS is placed on the substrate (15).
When forming the e-layer (16), if the laser beam (17) is scanned in the direction of the arrow, a striped low resistance portion (16°
), that is, a striped current path can be formed.

(G) Effects of the Invention According to the method of the present invention, by growing P-doped ZnSe while partially irradiating light onto the substrate, p-type ZnSe with low resistance can be formed partially, and this can be utilized. do,
A monolithic ZnSe light emitting element array or a ZnSe light emitting element having striped current paths can be realized.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of the MBE apparatus used in the method of the present invention;
The figure is a cross-sectional view showing an example of a ZnSe light emitting device array manufactured using the method of the present invention, and FIG. 3 is a plan view showing an example of a matrix type ZnSe light emitting device array also manufactured using the method of the present invention. , FIG. 4 is a perspective view for explaining a method of manufacturing a ZnSe light emitting device having striped current paths using the method of the present invention.

Claims (1)

[Claims] (1) Zn cell containing Zn, S containing Se
An e-cell and a P-cell containing P are prepared, and each stored material is ejected as a molecular beam from each cell, and when p-type ZnSe is grown on the substrate, light is partially irradiated onto the substrate. A method for manufacturing a ZnSe light emitting device, characterized in that growth is performed while irradiating.