Influence of nitrogen gas flow ratio on gallium nitride film growth using high-density convergent plasma sputtering device at room temperature

The influence of the nitrogen gas ratio on the gallium nitride (GaN) film growth has been investigated using a high-density convergent plasma sputtering device at room temperature. To obtain a highly reactive environment for GaN film growth, the convergent magnetic field lines assist the high-density plasma transport near the target surface. An orthogonal array in the design of experiments was used to effectively investigate GaN film growth conditions. To optimize the GaN film growth conditions, we focus on four sputtering parameters: (1) the N 2 gas flow ratio, (2) the inflowing ion current to the target, (3) the process gas pressure, and (4) the target-substrate distance. The N 2 gas flow ratio mainly characterizes the growth condition of c-axis oriented wurtzite-structure GaN films on an unheated glass substrate. The full width at half maximum of the rocking curve for the GaN(0002) peak position decreases to 3.9 ° in the growth condition with 100% nitrogen at room temperature.