JPS6242517A - Semiconductor vapor processing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] In a semiconductor vapor phase processing method using an oxygen-containing compound as a dopant, in order to prevent a decrease in efficiency due to the precipitation of target impurities due to thermal decomposition and a deterioration in crystal quality due to the contamination of oxygen. , utilizes halogen compounds and aluminum along with dopants.

[Industrial application field]

The present invention relates to a semiconductor vapor phase processing method, and more specifically, to an improvement in an impurity doping method in a semiconductor crystal vapor phase epitaxial growth method.

[Conventional technology]

Vapor phase epitaxial growth is used to form thin film crystals in the manufacturing process of II-V group compound semiconductors, and halogen is used in the closed tube method to transport group (I) elements with low vapor pressure. An open tube method is used to form multiple thin film layers or to obtain a crystal layer of a predetermined thickness.

[Problem that the invention seeks to solve]

Vapors of various substances are used as dopants for the vapor phase growth of compound semiconductors, but Fe(CO)5
, Cr<C0)6. (Cry,) CJ! When using dopants containing oxygen such as
s), (2) thermal decomposition progresses during doping, and target impurities are not introduced into the semiconductor, which poses the problem of not being able to obtain high-quality crystals.

For example, when Fe(Co)5 is used as a dopant, Fe thermally decomposes and deposits on the dopant introduction tube (dopant line), or oxygen becomes 11□0 and enters the crystal, changing its morphology. deteriorate.

The present invention was created in view of these points, and therefore provides a method for effectively utilizing impurities in semiconductors whose source is a substance containing oxygen.

[Means for solving problems]

1 and 2 are cross-sectional views of an apparatus used in an embodiment of the present invention.

1 and 2, 11 is a reaction tube, 12 is a gas introduction tube, 13 is a doping line, 4 is a substrate holder, 1
5 is an InP substrate, 16 is a boat containing an indium source, 17 is a heater, 18 is a cap, 19 is an exhaust pipe, 20
8 (1, Ga alloy, 21 is the auxiliary heater, 22 is the source indium.

In the method of the present invention, when a vapor of a compound containing oxygen atoms is used as a source of impurities when introducing impurities into a semiconductor crystal through the gas phase, in addition to the vapor of the compound, IIcβ, AsCe 3 .

It uses halogen compound vapor such as PCR3, CE2+ Br2, etc. In Fig. 1, the growth gas (PC
e 3 + 112 ) is supplied into the reaction tube 11 through the growth gas introduction tube 12, and dopant (Fe(CO)s + ) 12 ) gas is supplied into the reaction tube 11 through the doping line 13. When carrying out the above method, the growth gas is
, Ga, In, etc. after being brought into contact with liquid metals.

[Effect]

For example, in the case of Fe(CO)5, it is F
e and CO gas. The vapor pressure of Fe is low enough at the semiconductor manufacturing temperature that it precipitates on the doping line, but in order to prevent this precipitation, Fe is
, to a halogen compound such as Feα3. As a means of achieving this, a halogen element source is used simultaneously with an impurity source.

Further, CO generated by thermal decomposition is brought into contact with a substance that easily combines with oxygen, such as 1, and is precipitated as Al1203 and C (carbon).

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

To explain the vapor phase growth of InP with reference to FIG. 2, in order to epitaxially grow high-resistance InP, Fe(C
o,>s was used as a dopant. Fe(CO)5
+! When InP 12 is supplied into the reaction tube 11 through the doping line 12, the InP crystal on the substrate 15 becomes p
(growth temperature 690 °C, In source temperature 800 °C, Pα3 molar ratio 2 × 10−2 mol, gas flow rate 500 ml! 7 min, dopant gas flow m 100
m127 minutes). This is understood to be because Fe was deposited on the doping line 13, CO was introduced into the reaction tube 11, and carbon was doped into InP from this CO.

Note that the surface of the grown crystal became uneven.

Therefore, in addition to Fe(CO)5, pC, e3 vapor (PCe3+H2) is passed through the gas introduction pipe 12.
When Fe was supplied into the reaction tube 11 through the doping line 13, no precipitation of Fe was observed on the doping line 13, but the characteristics of the crystal were not much different from those of the p-type case described above.

Furthermore, as shown in Fig. 1, Fe(CO)5 and P
C) Gas containing ea vapor (Fe(CO)s + PCJ
! 3 + H2) with a 1:1 ratio of Ga and Aff placed in the doping line 12 and heated by the auxiliary heater 21.
When the alloy (indicated by reference numeral 20) was passed over and supplied to the reaction tube 11 (with Pαa+11z gas being supplied from the gas introduction tube 12), fnP crystals with a resistance value of 1O69 cm or more were vaporized on the substrate 15. phase-grown. In addition, Ga
- Instead of or together with the alloy i, an element or compound that combines with oxygen and whose combined product has a sufficiently low vapor pressure may be used, typical examples of which are trimethylaluminum, trimethylgallium, etc. .

According to the inventor's experiments, in addition to Fe (C5), Cr
The above method is also applicable to dopants such as (CO) 6 and Cr01-2. Furthermore, not only chloride-based vapor phase growth methods but also Ga i As containing octaβ.

In Aj! Thermal decomposition method of compound semiconductors such as As (M
It is also applicable to the O-CVD method), and it is possible to grow a high-resistance crystal not by doping oxygen but by introducing impurities at deep levels such as Cr and Fe.

〔Effect of the invention〕

As described above, according to the present invention, a crystal with good morphology without oxygen contamination can be obtained, and the efficiency of doping with impurities can be increased.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of embodiments of the present invention. In Figures 1 and 2, 11 is a reaction tube; 12 is a gas introduction pipe; 13 is the doping line, 14 is a substrate holder; 15 is an InP substrate; 16 is a boat, 17 is a heater; 18 is a cap, 19 is the exhaust pipe, 20 is Ga-Al! alloy, 21 is an auxiliary heater, 22 is source indium. This invention S! party example light side super Figure 1 The current situation is a folded circle. Figure 2

Claims (4)

[Claims] (1) The vapor of a compound containing oxygen atoms is passed through the doping line (13) to the gas phase reaction tube (11) as an impurity source.
A semiconductor vapor phase system characterized in that when introducing a halogen compound vapor into a semiconductor crystal on a substrate (15) disposed in a semiconductor crystal, a halogen compound vapor is introduced into a reaction tube (11) together with impurities through a gas introduction tube (13). Processing method. (2) Reaction tube (11) after contacting the vapor of the compound containing oxygen atoms and the vapor of the halide compound with the liquid metal (20) that combines with the heated oxygen in the doping line (13)
2. A method as claimed in claim 1, characterized in that the method is implemented in a. (3) The method according to claim 1, characterized in that an element or compound that combines with oxygen and whose combined product has a low vapor pressure is used together with or in place of the liquid metal. (4) The method according to claim 1, wherein the substance is trimethylaluminum, trimethylgallium, or a similar substance.