Surface chemistry of 1,1‐dimethylhydrazine on GaAs(100)

The thermal chemistry of 1,1‐dimethylhydrazine (DMH) on GaAs(100) has been studied by x‐ray photoelectron spectroscopy (XPS), temperature programmed desorption (TPD), and high resolution electron energy loss spectroscopy (HREELS). With the GaAs(100) at 150 K, DMH adsorbs molecularly and forms three‐dimensional islands. In subsequent TPD, molecular desorption occurs at 180 K with a high temperature shoulder extending to 400 K. No evidence was found for dissociation during the temperature ramp. However, dissociation does occur during adsorption at 400 K; N(1s) XP spectra and HREEL spectra indicate cleavage of the N–N bond. There are two products in subsequent TPD; dimethylamine and ammonia desorb at 490 and 580 K, respectively. There is no evidence for C–N bond cleavage at dosing temperatures up to 773 K. GaN is formed when DMH is dosed at surface temperatures above 600 K; carbon contamination is below XPS detection limits.