JP2500601B2 - p-type II-VI semiconductor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a p-type II-VI compound semiconductor having a large forbidden band used for a blue semiconductor laser or the like.

[0002]

2. Description of the Related Art II-VI group compound semiconductors containing S or Se have a large forbidden band and are used for blue semiconductor lasers and the like. Since it is difficult to obtain p-type conduction in this material system, a superlattice made of ZnTe and ZnSe was prepared and
A method of adding an acceptor only to the Te layer has been attempted (Japanese Patent Laid-Open No. 3-270278).

[0003]

However, the addition of an acceptor to the ZnTe layer as in the prior art cannot raise the acceptor concentration to 1 × 10 ¹⁸ cm ⁻³ or more, and the ultra-strain with a very large strain is introduced. Since it is a lattice, it has a problem of poor crystallinity.

An object of the present invention is to provide a p-type II-VI semiconductor which solves the above problems.

[0005]

The present invention is based on sulfur (S)
Alternatively, in a II-VI group compound semiconductor containing selenium (Se), a delta doping layer in which acceptors are added in a monoatomic layer shape, and at least a group VI atomic plane that is a first or second adjacent atom of the delta doping layer On the other hand, 1
% Of tellurium (Te), and a single or a plurality of the delta doping layer and the Te addition layer.

[0006]

Function: 2 × 10 ¹⁸ cm ^{−3 for} ZnSe and ZnS semiconductors
Since no acceptor can be added and the acceptor level is deep at 120 meV, the hole concentration at room temperature is 5 ×.
It cannot be more than 10 ¹⁷ cm ^-3 . Delta-doping the acceptor, and T on the group VI atomic plane adjacent to it
When e is added, part of Group VI atoms adjacent to the acceptor atom becomes Te atom. Since the Te atom has a function of increasing the concentration of the added acceptor and a function of shallowing the acceptor level, a part of the adjacent atoms becomes Te,
High-concentration doping can be realized, and the acceptor level becomes shallow. Since the addition of acceptor is delta doping,
The acceptors are arranged in a plane, and the probability of Te being adjacent to the acceptor impurity can be increased by simply adding Te in a plane.

[0007]

EXAMPLE FIG. 1 is a schematic view of a crystal structure showing an example of the present invention.

It was grown on a p-type GaAs substrate by the molecular beam epitaxy method. ZnSe layer 1 (thickness 2 nm) to which nitrogen (N) was added at 1 × 10 ¹⁷ cm ⁻³ and ZnTe _0.5 Se
_0.5 1 atomic layer of Te-added layer 2 and N of 2 × 10 ¹⁹
A p-type ZnSe semiconductor having 30 cycles of the delta doping layer 3 made of 1 atomic layer of ZnSe added with cm ⁻³ was obtained. The hole concentration of this p-type ZnSe semiconductor layer is 3 × 10 ^18.
It was very high at cm ^−3, and the resistance could be reduced to half by using it for the p-type cladding layer of the semiconductor laser.

The hole concentration of the conventional N-doped ZnSe layer is 5 ×
Although it is 10 ¹⁷ cm ⁻³ or less, in the present embodiment, the Te-doped layer 2 and the delta-doping layer 3 are adjacent to each other, and part of the second adjacent atoms of N in the delta-doping layer 3 become Te. , N was increased to 2 × 10 ¹⁹ cm ⁻³ , the acceptor level was also reduced to 80 meV, and the hole concentration was significantly increased. This is because the II-VI compound semiconductor containing Te is easier to add than Se and the acceptor level is shallow. In addition, the potential for holes is lower in the Te-added layer 2 than in the delta-doped layer 3, so that the Te-added layer 2 is transferred from the N acceptor in the delta-doped layer 3.
The holes move to and the average acceptor level is lowered.

In the above embodiment, Zn was used as the semiconductor material.
Although Se is used as N as the p-type impurity, the present invention is not limited to this, and other semiconductor materials such as ZnS and ZnCdSSe, and
Other p-type impurities such as Li and As may be used.

[0011]

As described above, according to the present invention, a II-VI semiconductor layer having a high hole concentration can be obtained, and a device such as a blue semiconductor laser can be realized.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

[Explanation of symbols]

 1 ZnSe layer 2 Te addition layer 3 Delta doping layer

Claims (3)

(57) [Claims] 1. Containing sulfur (S) or selenium (Se)
The II-VI group compound semiconductor has a delta doping layer to which an acceptor is added in the form of a monoatomic layer, and tellurium (Te) is present on at least one of the group VI atomic planes that are the first or second adjacent atoms of the delta doping layer. A p-type II-VI semiconductor having an additive layer and having one or more of the delta doping layer and the Te additive layer. 2. The p-type II-VI semiconductor according to claim 1, wherein the Te-doped layer contains 1% or more of Te. 3. The p-type according to claim 1, wherein the delta doping layer is one atomic layer of ZnSe added with nitrogen (N), and the Te addition layer is a ZnTeSe layer. II-VI semiconductor.