JPS5915985B2 - Decomposed species selective ion beam deposition method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a vapor deposition method for producing a high-quality thin film, and in particular, selects only desired ions by utilizing the difference in circular orbit radius depending on the type of decomposed species in the molecular ion state of a raw material gas. The present invention relates to a selective ion beam deposition method for selectively decomposed species, in which the decomposed species is deposited on a substrate.

' Conventionally, this type of thin film growth equipment includes sputtering and plasma CVD equipment. Taking the growth of a thin film of amorphous silicon as an example, in the case of amorphous, unlike single crystal, there are many tank ring bonds, which makes the film quality poor and it is difficult to obtain reproducibility. It was hot. Therefore, hydrogen gas is usually introduced during thin film growth to reduce tank ring bonds. However, in this case, the film thickness from an electrical and optical perspective is greatly influenced by the abundance ratio of decomposed species in the molecular ionic state, such as Si-H and F/HSi.

On the other hand, in conventional thin film growth methods using sputtering and plasma CVD, the film quality can be controlled to some extent by controlling the substrate temperature, RF power, degree of vacuum, etc.; The disadvantage was that it was difficult to control the ratio.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a decomposed species-selective ion beam evaporation method that can produce a high-quality thin film by appropriately controlling the bonds between the atoms constituting the thin film and impurities.

In order to achieve such an object, in the present invention, a gas that is a raw material for thin film growth is decomposed by glow discharge, further ionized to obtain decomposed species in a molecular ionic state, and the obtained molecular ionic decomposed species are decomposed by an electric field. At the accelerated stage, a magnetic field is applied and mass spectrometry is performed using the difference in the radius of the circular orbit depending on the type of decomposition species of the raw material gas to select only the desired decomposition species, and the selected decomposition species is uniformly decelerated to a low energy level such that the substrate on which the decomposed species is deposited is not damaged and the decomposed species can grow smoothly before being deposited on the substrate. Then, vapor deposition is performed.

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

FIG. 1 shows one embodiment of the present invention, in which 1 is a quartz tube for introducing the raw material gas for thin film growth, and 2 is for plasmaizing the raw material gas, that is, decomposing it by glow discharge and further ionizing it. 3 is a high frequency coil wound around the outer circumferential surface of the quartz tube 1; 3 is an electrode for accelerating the obtained plasma;
Reference numeral 4 denotes a mass spectrometer for selecting a desired decomposition species from the decomposition species of multiple types of molecular ion states in the accelerated plasma, and 5 a mass spectrometer for colliding the decomposition species selected by the mass spectrometer 4 with the substrate 4. It is a deceleration electrode to reduce the speed of. To operate this apparatus, first, a gas that can be used as a raw material for growing a thin film, such as silane (SiH4) gas for producing an amorphous silicon thin film, is introduced into the quartz tube 1.

The gas introduced into the quartz tube 1 is decomposed within the quartz tube 1, and the gas is in both a neutral and ionic state. At this time, a large amount of molecular plasma can be generated by increasing the decomposition power. Quartz tube 1
The decomposed species in the plasma that have reached the downstream part (the left part in the figure) of the plasma are accelerated by the electrode 3. The accelerated decomposed species are introduced into the mass spectrometer 4. In this mass spectrometer 4, a magnetic field is applied to the accelerated decomposed species, and only a desired decomposed species is selected from a plurality of types of decomposed species by utilizing the difference in the radius of the circular orbit depending on the type of decomposed species. The selected decomposition species are introduced into the deceleration electrode 5 and uniformly decelerated to a low energy level, for example, below several hundred EV, such that the substrate 6 is not damaged and the growth of the decomposition species is smooth. . The reduced and accelerated ions reach the substrate 6, where they are deposited and grown. As explained above, according to the present invention, all of the ionized decomposition species do not reach the substrate, and only the desired decomposition species are selected and reach the substrate. Very high quality silicon films can be produced.

In other words, the decomposed species-selective ion beam deposition method of the present invention has the advantage that it is possible to freely control the bonds between constituent atoms and impurity atoms, which greatly affect the electrical and optical properties of the film, and to obtain a high-quality thin film. be.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the present invention. 1... Quartz tube, 2... Coil, 3... Accelerating electrode,
4...Mass spectrometer, 5...Deceleration electrode, 6...Substrate.

Claims (1)

[Claims] 1 The raw material gas for thin film growth is decomposed by glow discharge,
Furthermore, the decomposed species in the molecular ionic state are obtained by ionization, and the obtained decomposed species in the molecular ionic state are accelerated by an electric field. At this stage, a magnetic field is applied to analyze the mass of the decomposed species caused by the raw material gas, and a predetermined decomposed species is determined. The selected decomposition species is uniformly decelerated to a low energy level such that the substrate on which the decomposition species is deposited is not damaged and the growth of the decomposition species is smooth. A method for selectively decomposed ion beam deposition, characterized in that the ion beam is deposited by reaching the substrate.