JPH0656580A - Shutter driving device for molecular beam cell - Google Patents

Abstract

PURPOSE:To obviate the generation of a shock at the time of the opening and closing actions of a shutter. CONSTITUTION:A shutter 4 of a molecular beam cell is operated to be opened and closed by a driving shaft 5 in a straight line direction shown by an arrow. This driving shaft is pinned 16 to a crank arm 15 of a crank device 14. This crank arm is pinned 18 to a rotary disk 17. The shutter acts the opening and closing as the rotary disk is rotated. The opening and closing speed of the shutter changes gently near opening and closing positions. The opening and closing of the shutter are executed by a slow start and a slow stop, by which the generation of the shock is obviated at all. The fall, etc., of flakes generated heretofore by the impact at the time of closing and opening of the shutter are eliminated. This device is particularly effective for execution of an ALE method and the production of films having good quality is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shutter drive device capable of performing slow start and slow stop operations of opening and closing a linear movement type shutter of a molecular beam cell in a molecular beam epitaxy apparatus.

[0002]

2. Description of the Related Art In a molecular beam epitaxy (MBE) apparatus, as shown in FIG. 3, a plurality of molecular beam cells 1 which are evaporation sources of required elements are attached to a growth chamber chamber 2 and protrude from each cell. A desired molecular (atomic) beam reaches the film formation target substrate to grow a desired crystal on the substrate. A shroud 3 cooled by liquid nitrogen is arranged around the molecular beam cell so as to prevent impurities and unnecessary gases from the heated molecular beam cell 1 and the like from reaching the film formation substrate, and captures these gases. I am trying. At the exit of the molecular beam cell 1, a plate-shaped shutter 4 is provided for blocking the molecular beam applied to the film formation substrate in order to control the crystal growth process on the substrate.

The shutter 4 shown in FIG. 2 is of a type that is operated in the direction of the arrow straight line to open and close the exit portion of the molecular beam cell 1. A shutter drive shaft 5 is attached to the shutter, and the drive shaft is operated by a shutter opening / closing operation device 6 attached to the growth chamber chamber 2. The operating device is a flange portion 2 provided in the growth chamber chamber 2.
_A flange portion 7 attached to ₁ and a flange portion 9 connected to the flange portion by a support rod 8 are provided, and a linear drive type actuator 10 by an air cylinder device is attached to the flange portion 9. The actuator has a cylinder 11 and a piston 12, and the shutter drive shaft 5 is connected to the piston 12. Opening / closing device 6
The other end of the vacuum seal bellows 13, one end of which is fixed to the flange portion 7, is fixed to the shutter drive shaft 5, and the drive shaft portion is vacuum-sealed. Linear drive type actuator 10
By driving the shutter drive shaft 5, the shutter 4 is reciprocally operated in the direction of the arrow in a predetermined linear direction range to open and close the exit portion of the molecular beam cell 1.

[0004]

As described above, although the linear drive type actuator 10 by the air cylinder device is used to operate the shutter to a predetermined opening / closing position, the piston 12 of the air cylinder device is at the stop position. An impact is generated each time the shutter is opened and closed, and the higher the speed of opening and closing the shutter and the higher the repetition rate, the greater the impact.
The impact is transmitted not only to the periphery of the mounting portion of the shutter opening / closing operation device 6 but also to the periphery thereof. This is because the piston 12 operates at high speed up to the shutter open / close stop position and stops by hitting the end face of the cylinder 11. In this respect, the structure of improving the stopping method of the piston or adding a shock absorber or the like is considered. There are things, but the prevention of impact is not yet perfect.

With the occurrence of such an impact, flakes and the like adhering to and depositing on the shutter in the growth chamber may be peeled off and fall to affect the film formation on the substrate and hinder the production of a good quality film. Become. Particularly, in the ALE (Atomic Layer Epitaxy) method in which monoatomic layer films are alternately stacked, the shutter 5 has to be opened and closed at a rate of once per second, so the impact is extremely large and the impact is not generated. It will also shorten the life of the shutter mechanism.

According to the present invention, when a linear movement type shutter of a molecular beam cell is opened / closed, a driving mechanism is used which has an opening / closing speed of a slow start and a slow stop, so that no impact is generated even during a high repetitive opening / closing operation. An object of the present invention is to provide a shutter driving device.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a shutter driving device for a molecular beam cell, including a linear movement type shutter,
A motor and a crank device for converting the rotational motion of the motor into a linear reciprocating motion and driving the shutter are provided.

[0008]

The rotation of the motor is converted into a linear reciprocating motion by the crank device, and the speed of the motion gradually decreases near the reversal point, reverses at zero speed, and gradually increases. Therefore, the linear movement type shutter driven by the crank device is slow-stopped or slow-started near the end point of the opening / closing operation, and no impact occurs.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of the embodiment, FIG. 2 is a characteristic diagram of shutter operation speed, and the same reference numerals as those in FIG. The linear movement type shutter 4 of the molecular beam cell 1 is connected to a shutter drive shaft 5, and the drive shaft is a crank device 14.
Is connected to one end of the crank arm 15 by a pin 16.
The other end of the crank arm 15 is connected to the turntable 17 by a pin 18. The rotary shaft 19 of the rotary disk 17 is a motor that rotates at a constant speed, for example, a geared motor 20 having a reduction gear.
The motor 20 is attached to a base 21 fixed to the flange portion 9 of the shutter opening / closing operation device 6. When the turntable 17 makes one revolution due to the rotation of the motor 20, the shutter drive shaft 5 reciprocates once, for example, the shutter 4
3 returns from the closed position to the closed position in FIG. 3 and then returns to the closed position, and the shutter is opened and closed by one operation.

The motor 20 rotates the turntable 17 at a constant angular velocity, and the opening / closing speed of the shutter drive shaft 5 and thus the shutter 4 changes as shown by the characteristic curve in FIG. When the shutter speed is zero, the shutter speed changes gently near the open / closed reversal position, and the shutter starts slow-moving and slow-stopping. No shock is generated and smooth opening / closing operations are repeated. You can

[0011]

Since the present invention is configured as described above, the high-repetition shutter in which the rotary disk 17 is rotated once per second (60 RPM) and the shutter 4 is opened and closed once per second is opened and closed. Sometimes it can be operated smoothly without generating shock, which is very effective in performing the ALE method in which films of different monoatomic layers are alternately stacked. Since no impact is generated when the shutter is opened or closed, the shutter can be broken, or contamination or particles can be prevented from adhering during film formation due to the flakes falling due to the impact, so that a good quality film can be manufactured. Further, since the opening / closing speed of the shutter is proportional to the rotating speed of the turntable of the crank device driven by the motor 20, by appropriately changing and adjusting the rotating speed of the motor, an optimum shutter opening / closing period, The cycle can be set arbitrarily.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a characteristic diagram of shutter speed.

FIG. 3 is a configuration diagram of a conventional example.

[Explanation of symbols]

 1 Molecular beam cell 2 Growth chamber 3 Shroud 4 Shutter 5 Shutter drive shaft 6 Shutter opening / closing device 14 Crank device 15 Crank arm 17 Rotating plate 20 Motor

Claims (1)

[Claims] 1. A molecular beam comprising a linear movement type shutter, a motor, and a crank device for converting the rotational movement of the motor into a linear reciprocating movement to drive the shutter. Cell shutter drive.