GaN - ICP-RIE Dry Etching

GaN - ICP-RIE Dry Etching

Material Name: GaN
Recipe No.: 8507
Primary Chemical Element in Material: Ga
Sample Type: Wafer
Uses: Etching
Etchant Name: None
Etching Method: Dry etching
Etchant (Electrolyte) Composition: The material used was nominally n-type and p-type GaN wafers. Seven samples were used for each experiment and prepared using similar photolithographic process. Before patterning, the samples were cleaned, dipped in DI water and dried using N2 gas. Photo resist was spin coated onto all samples, forming ~ 1.5 µm layer. After that, all of them were etched by inductively coupled plasma etching using various gases in Oxford Plasmalab 80Plus system. For these experiments, etch rates were evaluated as a function of gas flow rate and DC bias. The conditions consisted of 100 W ICP power, 250 W RIE power and 600 W RF power. Prior to etching patterned samples, a simple set of experiments were conducted to get an understanding of how changes in gas composition affect the etch rate. For this experiment, the Ar flow rate was varied from 0 sccm to 60 sccm meanwhile the Cl2 flow rates and the chamber pressure were held constant at 60 sccm and 5 mtorr, respectively. After that, individual sample was loaded into the chamber, centered on platters with the oxidized side exposed to the upper electrode. Immediately after the samples were removed from etching system, they were dipped into acetone to remove the photo resist. The etch rates were measured from the depth of the etched features with a scanning electron microscope (SEM) after the removal of the PR layer. Surface morphology, etch anisotropy, wall angle and sidewalls undercutting of the etched GaN was evaluated with SEM model JSM-6460 LV while ULTRAObjective AFM is used to measure the surface roughness. All the fabrication processes were repeated using Cl2/H2 gases while maintaining the same conditions; 100 W ICP power, 250 W RIE power, 600 W RF power, 60 sccm Cl2 flow rates and 5 mtorr for chamber pressure.
Procedure (Condition): No data
Note: No data
Reference: SITI AZLINA ROSLI, AZLAN ABDUL AZIZ & MD ROSLAN HASHIM, ICP-RIE Dry Etching Using Cl2-based on GaN, Sains Malaysiana 40(1)(2011): 79–82.