| 摘要 |
PURPOSE:To suppress abnormal diffusion in the lateral direction just below the diffusion mask up to such a degree as resulting in no problem on practical use by executing heat processing to the surface of GaAs wafer under the oxygen ambient in order to form an oxide film before deposition of insulating layer for diffusion mask. CONSTITUTION:After washing a GaAs single crystal wafer 5 using an organic solvent, acid is washed out by sulfuric acid or hydrofluoric acid etc. Thereafter, a wafer 5 is set within the CVD furnace for depositing Al2O3 film and is subjected to the heat processing at the temperature of 400 deg.C for about 10min under the oxygen gas ambient at a flow rate of 1l/mm.. Then, the CVD is carried out using the triisobutyl aluminium as the source and thereby the Al2O3 film 1 is deposited in the thickness of about 1,500Angstrom . Moreover, a diffusion window 3 is formed in the form of groove in the width of about 5mum. Zn 4 is diffused in the depth of about 1mum at the temperature of 700 deg.C. Thereby, abnormal diffusion 6 in the lateral direction is kept very small. |
