Sumant Katiyal

Development of fast heating electron beam annealing setup for ultra high vacuum chamber

We report the design and development of a simple, electrically low powered and fast heating versatile electron beam annealing setup (up to 1000 °C) working with ultra high vacuum (UHV) chamber for annealing thin films and multilayer structures. The important features of the system are constant temperature control in UHV conditions for the temperature range from room temperature to 1000 ºC with sufficient power of 330 W, at constant vacuum during annealing treatment. It takes approximately 6 min to reach 1000 °C from room temperature (∼10(-6) mbar) and 45 min to cool down without any extra cooling. The annealing setup consists of a UHV chamber, sample holder, heating arrangement mounted on suitable UHV electrical feed-through and electronic control and feedback systems to control the temperature within ±1 ºC of set value. The outside of the vacuum chamber is cooled by cold air of 20 °C of air conditioning machine used for the laboratory, so that chamber temperature does not go beyond 50 °C when target temperature is maximum. The probability of surface oxidation or surface contamination during annealing is examined by means of x-ray photoelectron spectroscopy of virgin Cu sample annealed at 1000 °C.

Effect of lattice strain and annealing on the BiFeO3 films

BiFeO3 films have been grown on SrTiO3 and NdGaO3 substrate using pulse laser deposition technique. The films are found highly oriented and single phase in nature. The film grown on SrTiO3 was further annealed in vacuum at 800°C that showed large distortions. On the other hand high temperature Raman spectra collected on films grown on NdGaO3 substrate upto 773 K showed that the rhombohedral structure remains robust up to this temperature.