| 摘要 |
PURPOSE:To obtain IC of GaAs by decreasing Cr which is added in an element forming region to the appropriate depth, and avoiding the decrease in the amount of Cr addition in an element separating region. CONSTITUTION:Si ions are selectively implanted in a semi-insulating GaAs substrate 1 to which Cr is added two times, and an N type source 2, a drain 3, and a channel 4 are formed to specified depths. Then mixed gas of SiH4 and O2 is thermally decomposed, and a thick SiO2 film is formed. Etching is performed to the specified thickness at the specified locations by using a resist mask. An SiO2 film 5 whose depth is determined by the thickness of the impurities in the regions 3-5 is provided. An element separating region A is exposed. Si3N4 6 is coated and treatment is performed in H2 at about 800 deg.C. Then, Cr is moved to SiO2 in the element forming region wherein Si is added, and electric compensation by Cr is decreased. Activating rate of si is increased, and high electric mobility is obtained. Cr does not get out in the other part, and high resistance can be maintained. |
