JPS6024180B2 - Film preparation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, an impurity element having a dish value or a value V and hydrogenated silane are filled in the same cylinder, and polysilane (
After chemically activating, decomposing or reacting a reinforcing gas consisting of Si phantom Hy (x≧2, y≦4), monosilane (Si) or polysilane (hereinafter simply referred to as associated silane) in an associated state, The purpose is to form a film of silicon or a silicon compound (mixture) on the formation surface.

In the present invention, such a coating has a structure in which bulk crystal particles are superposed, and the crystal particles may be amorphous or semi-amorphous depending on the case.
amorpho melon, this semi-amorphous Q skin si-amor
pous, Simi-c Hisji or Quasi-
The purpose of this method is to produce a film with c his (c his can be said to be 1). Furthermore, the present invention provides that when a polysilanization reaction or an associative silanization reaction is performed by filling a cylinder with hydrogenated silane (a compound gas consisting only of hydrogen and silicon), particularly monosilane, silane or the silane is filled with helium as a diluent gas. An active gas is used, and the cylinder internal pressure (P(
The relationship between k9/c*)) and silane concentration (N (%)) is N
The purpose is to experimentally prove that XP and 300% kg/C fins, particularly preferably NXP 2500% k9/C but NSI 00%, is particularly promoted, and to promote the multistate or associated state of such polysilanes or associated silanes. It is said that

Conventionally, silane has been monosilane (Si specific boiling point 11〆0, melting point 185〆0), and polysilane with multiple bonded silicon hydrides (Si phantom Hy x≧2, y≧4) is unstable and is not practical. It was believed that it did not exist.

Furthermore, since monosilane is a gas and its molecules separate from each other, it was considered most appropriate to write it as ``SjH4''. On the contrary, it tends to become polysilane or associated silane, and at room temperature or near room temperature (generally below 100°C), tens of
It has been found that millions of silicones polymerize or associate with each other.

In addition, it has been found that these polymerized or associated molecules are even more preferable in coatings prepared by laminating bulk clusters as in the present invention. In particular, when forming an amorphous semiconductor (hereinafter referred to as AS) or a semi-amorphous semiconductor (hereinafter referred to as SAS) at a temperature of 70,000 or below, which is the crystallization temperature of silicon, or particularly 500,000 degrees or less, the film is I was able to create a structure in which the classes were overlapped (stacked). In particular, unlike a polycrystalline semiconductor with clear boundaries, which is formed at a temperature above the crystallization temperature, this lumpy class structure does not necessarily have clear grain boundaries, and interface states are concentrated at these grain boundaries. A major feature is that it does not exist. Furthermore, when silane and diborane or phosphin diluted with hydrogen or the like are mixed in a doping system, which is conventionally known, since the silane is already in an associated state, boron or phosphorus is only present outside the class. They cannot be bonded (combined), and boron or phosphorus is distributed non-uniformly in the microscopic area.

That is, in the formed film, many impurities are concentrated in the periphery of the silicon film, and are substantially unevenly distributed locally in the silicon film. For this reason, the so-called ionization rate Np where they act as acceptors or donors with respect to the amount added is
=acceptor concentration/added boron concentration is as low as 3 to 30%.

However, on the other hand, when diborane or phosphin is added to the cylinder at the same time as silane as in the present invention, the ionization rate Nn of phosphorus acts as ~100%, and the ionization rate of boron also increases by an order of magnitude from 95% to 99%. It is now possible to improve the ionization rate.

In the present invention, when forming silane in an associated or associated state in a cylinder, at the same time, an m-valent or V-valent impurity such as diborane, phosphin, or arsine is added to the cylinder at a rate of 10 times the silane (100 times the volume of the silane).
1 times the volume) to 10 mol% (10 times the volume of silane)
% volume).

Then, the impurity was distributed homogeneously inside the crystal layer, and the acceptor or donor center could be ionized at a rate of 98 to 100%. This was an extremely excellent effect considering that when the m-valent or V-valent impurity cylinder and the silane cylinder are mixed immediately before introduction into the reaction system, the ionization rate is 3 to 30%. Embodiments of the present invention will be described below with reference to the drawings.

Example 1 A conductive substrate or an insulating substrate was used as a substrate having a surface to be formed.

In FIG. 1, the substrate 15 has a thickness of 200 to 1000 mm, and a maximum size of 10 mm, and is arranged on a quartz board 14.

It was formed parallel to the gas flow. This reaction tube is 0.
It uses inductive energy with a frequency of 1 MHZ to 1 yesterday Z, typically 50 days 2,13.58 MH2
, 2.4&HZ.

In FIG. 1, a high frequency of 13.58 MHZ was used. The induction energy was supplied by a capacitive coupling method through a pair of electrodes 2 and 3 so that the entire reaction tube 1 was uniformly discharged.
Furthermore, this discharge is performed by providing an activation chamber 1 for a reactive gas at a position away from the formation surface, and polymerized or associated silicide gas such as polysilane or associated silane is chemically treated in the activation chamber 1 by electromagnetic energy (induced energy). Activation, decomposition or reaction is carried out, and this process is further advanced during the spraying process, and the lump-like particles are randomly layered on the substrate 15 to form a film. The reactive gas is silane in a polymerized or associated state (SkHy x and 2 y≧4, m
SiH4) from 7 to 1, and at the same time to this silicide gas an impurity gas such as diborane (&day 6) from 100 to 1
0 mol % mixed, and further 0 to 9 by He inert gas.
A bomb with 7% dilution was connected to 8. In addition, in terms of V value, phosphorus, phosphorus, and antimony are phosphine (PH3).
, arsine (AsH3), and stibine (SbH3) were added to the silicide gas in the same way, and then 0 was added to the cylinder with He.
Diluted ~97% and connected to 9. The reaction tube was made sufficiently thick to reduce the influence of the tube wall, and its outer periphery was cooled with water to prevent nucleation from forming on the wall.

This is very different from the reduced pressure vapor phase method, which assumes that the temperature of the wall surface is the same as that of the substrate, and attempts to actively attach the polycrystalline silicon formed on the wall surface to the substrate surface.

The substrate 15 was heated in a resistance heating furnace 6, and the reacted gas and elemental products were evacuated 13 through a needle valve 10, a stop valve 11, and a vacuum rotary pump 12.

The reactive gas used was primarily a silicide gas, in which the silane was diluted to 50-3% in a cylinder with an inert gas, such as IJ hume.

Of course, 100% silane may also be used. Reaction system (furnace 5
or activation chamber 1) is 10-3 to 1 and especially 0.0
The pressure was adjusted to 0.05 to 5 tons by introducing reactive gas and evacuation.

Generally at 500KHZ, 1~2 Prr, 13.58M
0.1-3on for H2, 0.00 for 2.45GH2
The optimal amount was 5 to 0.1 ton. In the present invention, the pressure inside the cylinder will be described later in FIG.
k9/enemy (50%) or more, particularly preferably 50~
The pressure was set to be over 10k9/ground. Then, the monosilane molecules decompose in the cylinder and undergo a polymerization reaction with each other to obtain a polymer, or the monosilane molecules bond due to their hydrogen (
The silanes were made to form associative silanes that associated with each other through hydrogen bonds (hydrogen bonds).

This polymerized or associated silane aggregates during activation in the reaction system, even though it is in the gas phase, and forms so-called semi-crystalline clusters that promote more stable crystallization. It was extremely effective.

For this reason, hydrogen is unsuitable as a carrier gas because it tends to re-hydrogenate the unpaired bonds generated by the decomposition of silicon, as it promotes multiple or associated states within the cylinder. Highly preferred was He. He has an ionization voltage of 24.57 eV,
It is larger than the 10-1&V of other commonly used diluent gases, and the heat conductivity coefficient is 0.1V, which is about 3 times that of other gases.
The temperature was 12 cal/mHg°C, which was convenient for improving the uniformity of the formed film. The reactive gas and the substrate were heated from a heating furnace 8, and heated from room temperature to 700 oo.

As is clear from the drawings, the reactive gas is placed on the supply source side (cylinder side) away from the substrate by induced energy,
All reactive gases were excited or activated and decomposed using induced energy. In addition, this activated product can be added at room temperature to 2
It was heated to 0000. In this manner, the activated or decomposed reactive gases coagulated and associated with each other.
In terms of physical properties, they coagulate with each other to form a plurality of lumps (clusters) in which silicon is in an active state in the reactive gas. Furthermore, since the activated clusters were formed into a film on the substrate, some of the hydrogen was separated, and plate-shaped or hemispherical clusters could be formed on the substrate, overlapping each other. For this reason, the classes that overlap in a flat or hemispherical shape seek a stable state within the energetically possible range during the flight, so the distance between electrons varies widely, and the coordination of the atoms is Stable direction (angle)
It was found that the As a result, the electron microscopic diffraction photograph of the formed film showed a mixture of a halo indicating an amorphous structure and a spot or linear ring-like semiregular image indicating a crystallized structure. Second
Figures A and B summarize the process of forming a silicon cluster on a substrate from silane in the above reaction process, with B showing the reaction process of polysilane and A showing the reaction process of associated silane.

That is, in state 1, m silanes such as monosilane (
m(SiH4)) is activated in state D (m(siH4))
It further decomposes or reacts in the state plate, resulting in the active class Yu (lump) s flow day ki or si auspicious day ticket +2.

Here, m, n, m', n' represent arbitrary constants, and SiH*
indicates a state in which the Si-day bond has energy and is activated. They associate or agglomerate with each other during husks, becoming chemically active class 16. To schematically show this state, hydrogen mainly gathers around the Si class layer 16 to form a shell 17 state. Further, in W, a film 20 is formed on the substrate 15 in the form of a flat plate or a hemisphere. For this reason, the contours of the periphery of the crystals were not necessarily as clear as those of ultra-dense polycrystals, but were rather blurred even when observed under an electron microscope.

Furthermore, the size and shape of the cylinder also depend on the pressure of the cylinder (
It is greatly affected by the initial state of the reactive gas), the frequency of the induced energy, the glue-flying time due to the power, the pressure, and the substrate temperature. However, when examined under a transmission electron microscope (TEM), the mass had a diameter of 100 A to 10 mm, was generally circular, and had no sharp corners.

Since such classes 20 are piled up one after another on the board,
Furthermore, they overlap each other. For this reason, state W, which is the process of film formation, rather disturbs the crystallographic regularity, and the initial state and activation of the reactive gas and the association (agglomeration) in the fly are in the gaseous state. Nevertheless, the feature of the present invention is that it promotes crystal-like regularity, particularly regularity in the coordination direction. Furthermore, the thickness of each class layer formed into a film is 5 to 50.
0A, and its effective diameter was 100A to 10.0F in experimental results. In addition, the higher the cylinder pressure of silane or a gas made by diluting silane with an inert gas, the higher the concentration of silane is, for example, 3%.
In the case of 10%, 50%, 100%, Fig. 3 curve 22
The pressures are set to be higher than the so-called general curve 21's 3, 1, 2, and 1 atmospheres, such as 10 atmospheres (atmospheric pressure), 3 atmospheres, 6 atmospheres, and 2 atmospheres. , making it easier to make class evening chunks and making them bigger. Furthermore, if these pressures are set to 150 atm, 5 atm, 1 atm, and 5 atm or more as shown in curve 23 in Figure 3, the number of classes formed will be 2 to 5 times as large as 3000 atm.
I was able to do up to 10 screams. When the carrier gas is hydrogen, the material becomes amorphous with many recombination centers due to the sputtering effect, even with a weak electric energy of 10 to 20 W due to induction energy. Furthermore, it has been found that when the temperature is lower than the conventional 200 to 55,000, the crystallinity within the cluster becomes amorphous, and the thermal energy during flight is also important. In the present invention, diborane and phosphin are added as P- or N-type conductivity type impurities to the same cylinder at the same time as silane at a predetermined concentration.

This way, when creating a multiplex or association state in the cylinder,
Boron or phosphorus could be added homogeneously to the inside (bulk) of the lump. Although this method of the present invention has the disadvantage that the conductivity of P or N type in the formed semiconductor film cannot be freely controlled, it is preferable to fill the same cylinder when the conductivity is always the same as in a mass production line. It has the characteristic of being easy to operate.

For this reason, P-type, 1-type, and N-type semiconductor films are stacked to form a P
When trying to make N junctions, PI junctions, and NI junctions, the conventional method has a 1 to 1 pi arc (electrical conductivity of 10-4 to 10- 2 (0 arc) -
1), in the present invention, 0
．． Even at 1 to 1 mol %, it was possible to lower the electrical conductivity to 10 to 0.10 (electrical conductivity 0.1 to 10 (0 arc) -1).

In particular, the fact that the same electrical conductivity can be obtained by lowering the amount of impurities added means that unnecessary impurities, or carriers, exhibit impurity scattering, lowering mobility, and forming impurity recombination centers. This makes it extremely preferable as a semiconductor material because it can reduce the degree to which it becomes a carrier killer.

Furthermore, in the present invention, a gas phase reaction is caused by mixing silane to which siborane, phosphin, or arsine is added, ammonia as a nitride gas, oxygen as an oxide gas, or methane as a carbide gas, and causing a gas phase reaction.
<x<4), Sj02★(0<x<2), SICx(0
<x<1) and the inside of the energy band is 1.2~
Instead of 1.7 eV, it is further 1.6 to 3. Project V and its N
, 0 or C to make a P- or N-type semiconductor or semi-insulator proportionally increased.

It goes without saying that the present invention is effective not only for semi-amorphous films but also for amorphous semiconductor films or semi-insulator films.

Furthermore, if the pressure inside the cylinder is maintained for a long period of 1 to 6 months, the polymerization or association state will gradually progress and the size of the lumpy particles formed will be 3 to 1 M.
It's gotten bigger. In addition, the pressure in the present invention refers to the pressure at the time of filling the cylinder or the maximum pressure of the cylinder, and if the reactive gas in the cylinder is used after filling, the pressure will be reduced. Needless to say, a gas such as lotus compound in which polymerized or associated impurities, which are reactive components produced by the process, are sufficiently mixed, can be obtained from the cylinder.

[Brief explanation of drawings]

Figure 1 shows a schematic diagram of a reaction apparatus for producing a semiconductor film used in the present invention, Figure 2 shows the reaction process of the present invention, and Figure 3 shows the pressure inside the cylinder and silicification of the present invention. Shows the relationship with the concentration of physical gases. Younger brother diagram Figure 1 Traditional bow diagram

Claims (1)

[Claims] 1. III-valent or V-valent impurities are added to a film to be formed using a cylinder in which diborane, phosphin, or arsine is added to hydrogenated silane made of monosilane or polysilane, or the silane diluted with helium. A method for producing a film in which added silicon or a compound (mixture) of silicon is formed, wherein the cylinder has a silane concentration (N (%)) and a cylinder internal pressure (P (kg/cm^2)) of N× P≧
300% kg/cm^2 However, N≦100% A method for producing a film. 2. In claim 1, a reactive gas maintained at room temperature to 700°C and supplied into a reactor at 10^-^3 to 10 torr is supplied with a frequency of 500 KHz to 10 GHz.
A method for forming a film, comprising: applying induction energy at a frequency of , to form a semi-amorphous film partially mixed with an amorphous or crystalline structure on the surface to be formed in the reactor. 3. In claim 1, silicon or a silicon compound (mixture) to which III-valent or V-valent impurities are chemically activated, decomposed or reacted by induced energy.
P has a structure in which large clusters are superimposed on the surface on which it is formed.
Or a film forming method characterized by producing an N-type film.