JPH0323299A - Growth method for compound semiconductor crystal - Google Patents

Abstract

PURPOSE:To apply atomic-layer epitaxy with a self-limiting characteristic by forming one layer of the adduct of the alkyl compds. of the group III element and group V element constituting the semiconductor on a semiconductor substrate and then bringing the surface of the adduct layer with a reducing gas at a higher temp. CONSTITUTION:One semiconductor layer 4 (substrate) arranged in a crystal growth device (reaction tube 1) is brought into contact with the adduct 8 of the alkyl compds. of the group III element and group V element constituting the one semiconductor to deposit one layer of the adduct 8 on the layer 4. The layer 4 deposited with the adduct 8 layer is brought into contact with a reducing gas (e.g. H2) at a temp. higher that the contact temp. of the adduct 8 to grow a single crystal layer 9 of the compd. semiconductor of the group III element and group V element. (CH3)3In.P(CH3)3 is exemplified as the organometallic adduct compd.

Description

Detailed Description of the Invention (Required 4a) The present invention provides improvements in compound semiconductor crystal growth methods, particularly utilizing atomic layer epitaxy that grows crystals in units of atomic layers [Industrial Application Field] This invention relates to improvements in growth methods, particularly improvements in methods for growing compound semiconductor crystals using atomic layer epitaxy, in which crystal length is controlled in units of atomic layers. improve performance,
Furthermore, with the aim of realizing compound semiconductor crystals with physical properties not found in compound semiconductor crystals manufactured using conventional methods and developing electronic devices with new functions, compound semiconductor crystals and their impurity concentrations have been reduced to an atomic layer. It is strongly recommended that students pray M in units. The conventional methods for lengthening compound semiconductor crystals in atomic layer units are explained below. For example, when forming a monoatomic layer of InP on an InPTE plate, the MO-CVD method is used, and the forming temperature is 3.
Trimethylindium C (
CHI )ff I fl) or triethyl indium ((C.H,), Inl and phosphine (PH3)
and are alternately supplied to Gosakagami. Supplied to Motosakaue (C
H,)3In or (C.Hs)sln is adsorbed onto the 1& plate with a portion of the methyl group (cH,-) or ethyl% (CzHs-) remaining. Since the surface of the base plate is covered by the remaining methyl or ethyl groups, only [(CH2))In or (CtHs)iln, which corresponds to an n monoatomic layer, is adsorbed onto the substrate, and no further It is not attracted to thickness. Next, PH. When In is supplied, these remaining methyl groups or ethyl groups are decomposed and removed, and In and P are combined to form In. P molecules lit are formed on the substrate by the self-lifting effect. [Problem to be Solved by the Invention] However, when a compound semiconductor crystal is grown in atomic layer units by alternately supplying raw material gas onto a substrate, a In principle, there is a time when the elements forming a compound semiconductor exist in atomic form. There is no particular problem when growing a compound semiconductor crystal made of the same elements as the constituent elements of the substrate on a substrate, but it is difficult to grow a compound semiconductor crystal made of an element different from the horizontal elements of the substrate. In the case of taxial growth, interdiffusion of atoms occurs near the hetero interface, making it difficult to form a steep hetero interface. It also becomes difficult to control the impurity concentration. The purpose of the present invention is to eliminate these drawbacks,
To provide a method for growing a compound semiconductor crystal, which is capable of forming a sharp hetero-interface and controlling a steep impurity concentration with a density of a single atomic layer. It is in. [Means for Solving the Problems] The above object is to form a semiconductor layer (4) disposed in a crystal growth apparatus with an alkylated compound of a group V element and an alkylate of a group Adduct with alkylate (8)
One layer of the adduct (8) is placed on the semiconductor layer (4) of the one above by contacting the two layers of the adduct (8).
A reducing gas is brought into contact with the semiconductor 1 (4) of the above 1 on which the layer is deposited at a temperature higher than the contact temperature of the above adduct, and the above group Ⅰ element and the above group Ⅰ element are combined. This is achieved by the compound semiconductor crystal lengthening method of lengthening a compound semiconductor single crystal 11 (9). [Function] In the compound semiconductor crystal growth method according to the present invention, for example, when growing an InP crystal using the MO-CVD method, an organometallic adduct compound of InP,
For example, using (CHyu), 10P(CH,)z, (C
H)), In'P (CHs)z supply and H purge are performed alternately. (CHs) was supplied to the substrate surface heated to 300°C.
), In 'P (CHI )) is a methyl group (CH!
) with some remaining [(CH,). In-P (C
H-). , where n, m = 0 to 3) is adsorbed to the substrate surface, (CH3 )! In-P(CH3)3
Even if the supply of
CH, )- is only adsorbed onto the base slope and no further adsorption occurs. Next, the base temperature was raised to 400°C and H. When supplying (CHs)-In-
The methyl group of P(CH3)- is decomposed and removed to form a single layer of InP single crystal. As a result, a single <rnP single crystal layer is formed in which In and P do not exist in the atomic state, so interdiffusion of atoms at the Kaicho interface does not occur. By repeating the above steps, atomic layer upitaxy, in which InP single crystals are grown layer by layer, becomes possible. [Example] Hereinafter, with reference to the drawings, regarding a compound semiconductor crystal growth method according to an example of the present invention, inP is grown by atomic layer epitaxial growth on an InP (100) substrate using the MO-CVD method. Let's take the case of cheating as an example. See Figure 2 Figure 2 is a diagram of the equipment used for atomic layer epitaxy, where 1 is a quartz reaction tube and 2 is connected to a vacuum pump (not shown). It is an exhaust system, 3 is a susceptor for placing the board 4, and 5 is a high frequency power supply P! 6 and 7 are gas switching valves. 1a and 1b, an InPi plate 4 is placed on the susceptor 3, the internal pressure of the reaction tube l is maintained at approximately 20 Torr using the exhaust system 2, and the InP substrate 4 is heated using high frequency heating 85. Heat to approximately 300°C. (CHs) I In-P (CH,), generated by passing a hydrogen carrier through a bubbler (not shown) containing (CH- Flow rate 10 into reaction chamber 1 through
03 CCM was supplied for X seconds, and 1 of trimethylindium trimethylphosphine adduct 8 was added to the base 4.
Deposit layers. Next, the gas switching valve 7 is switched to stop the supply of (CHs)s In'P (CH-)3 into the reaction chamber 1, and exhaust it to the outside of the system.
P toad vi. 4 is heated to 400° C., and H8 gas is supplied into the reaction chamber 1 for about 60 seconds through the gas switching valve 6 to grow an InP single crystal layer 9 on the InP substrate 4. See Figure 3. From the results of repeating the above steps for 1701'1 period, the ratio of the growth film thickness of the InP single crystal per 1 period to the film thickness of 1 InP molecular layer and the (CHz)z per llil period.
Figure 3 shows the relationship between In-p (CH!)s and the supply time χ. When the supply time X reaches 4 seconds, the InP film thickness is saturated, and even if the supply time The results showed that self-lifting atomic layer epitaxial growth to II film thickness was possible. In addition, as an organometallic adduct compound, the above-mentioned (CH
, ), I n ' P CCHs ) In addition to Ga,
It is possible to use an adduct compound of an alkylated product of a Group I element such as In, Affi, etc. with a methyl group, ethyl group, etc. and an alkylated product of a Group V element such as As, P, etc. with a methyl group, ethyl group, etc. Also, when supplying hydrogen to remove remaining methyl or ethyl groups, ultraviolet rays may be irradiated instead of increasing the temperature of the substrate, and
Heated hydrogen may also be supplied.

(Effects of the Invention) As explained above, in the method for growing compound semiconductor crystals according to the present invention, an adduct compound of an alkylated compound of a group Ⅰ element and an alkylated compound of a group Ⅰ element is brought into contact with a substrate to form the adduct. One layer is deposited, and then a driving gas is supplied to decompose and remove the alkyl groups to lengthen the ■/V group compound semiconductor crystal in atomic layer units. ■・■ Without existing in an atomic state
Since the atomic layer epitaxial alignment of the group compound semiconductor is performed, especially when forming a heteroepitaxial alignment, interdiffusion of atoms at the alignment interface does not occur, so a steep hetero-interface is formed. In addition, it becomes possible to control steep impurity concentrations with density on the order of atomic layers.

[Brief explanation of the drawing]

FIGS. 1a and 1b are process diagrams illustrating a method for lengthening a compound semiconductor crystal according to an embodiment of the present invention. FIG. 2 is a diagram showing the structure of an apparatus used in the compound semiconductor crystal cutting method of the present invention. Figure 3 shows (CH-) s l n-P (CHi
) s supply time and InP growth film thickness/I n P 1
It is a graph showing the relationship with the molecule II film thickness. DESCRIPTION OF SYMBOLS 1... Reaction tube, 2... Exhaust system, 3... Sustainer, 4... Semiconductor substrate, 5... High frequency heater, 6, 7... Gas switching valve, 8... Adduct Layer 9... lnP single crystal layer.

Claims (1)

[Claims] An adduct (8) of an alkylated product of a group III element and an alkylated product of a group V element constituting the first semiconductor is added to one semiconductor layer (4) arranged in a crystal growth apparatus. Let me come into contact with you.
One layer of the adduct (8) is deposited on the first semiconductor layer (4), and a reducing gas is applied to the first semiconductor layer (4) on which the one layer of the adduct (8) is deposited. A method for growing a compound semiconductor crystal, comprising growing a single crystal layer (9) of a compound semiconductor of the Group III element and the Group V element by contacting them at a temperature higher than the contact temperature.