GAS INJECTORS

Gas injectors are used in gas-source MBE and CBE systems to generate a stable molecular beam with uniform intensity. They also use to mix different gases, of the same group, to achieve high degree of material composition uniformity. VESCO-NM gas injectors are adapted for most gas-source MBE and CBE systems. Our gas injectors have independent 1/4 inch VCR male gas inlet and are equipped with high-temperature (200°C max) normally-closed pneumatic actuators. Cracking zone contains 0.25” OD inner tube and 0.75” OD outer tube and PBN cone to achieve high uniformity on the substrate. The single heater can reach up to 1250o C There are two types of gas injectors: Low temperature (< 100°C) for on- substrate cracking and high temperature (> 600°C) to decompose the species before impinging on the substrate. Normally the complete gas injector source package consists of:

• Gas injector source
• Pneumatic run/vent actuator assembly 
• Gas handling system
• Power Supply and temperature controller

The figure below illustrates pneumatic valve assembly. Valve 1 and 2 are normally closed. During growth valve 1 is opened and valve 2 is closed, valve 2 is opened during venting. Port A (Run line) is connected to the gas cabinet, while port C (Vent line) is connected to the vent pump. Port B (process) is connected to the reaction chamber via gas injector inlet port.

Key Features:

• Compatible with all MBE machines
• High reliability and long life time
• Operating temperature up to 1200o C 
• Low power consumption 
• Optional: Integrated water cooling, standoffs, and shutter

Source Specifications:

• Mounting Flange…………….……….………………………….4.5” 
• In-vacuum length…….………..…...............................................9.7” 
• In-vacuum tube diameter…………..….……………….………...2.4”
• Water cooling coil OD…………………………….…………0.1875”
• Front cone………………………..…………..…………………PBN
• Conductance tube………………………………………… Tantalum
• Bake out temperature……………………………   …….. 200° C
• Maximum gas inlet………………………………………………....1
• Number of Run actuators……………………………………..……1 
• Number of Vent actuators………………………………………….1
• Gas inlet………………………………….…………….¼ inch VCR
• Typical operating temperature……………………………….950o C
• Maximum operating temperature…………………………...1200o C
• Maximum outgassing temperature.………………………....1250o C
• Heater……………………………………...single tantalum filament
• Thermocouple……………………………………………….Type C
• Power supply……………….single power supply (800