Structural characterization of Ca-ion implanted GaN

Results of a systematic study of damage generation and accumulation until amorphization induced by 180 keV Ca⁺ implantation in GaN films at liquid-nitrogen and room temperature are compared. The as implanted films show an expanded lattice. An initial amorphous component was found after implantation with a dose of 3×10¹⁴ and 8×10¹⁴ cm^-2 at liquid-nitrogen and room temperature, respectively. The mechanism of amorphization is discussed and accumulation of amorphous clusters seems to be the reason for the collapse of the GaN crystalline state