| 摘要 |
PURPOSE:To improve dielectric strength without increasing the number of process, by thinning an oxide film under a field plate at the same time when the oxide film is opened by etching. CONSTITUTION:An SiO2 film 2 is provided on an N type Si-substrate. The SiO2 film increases gradually in its thickness, as a base 3 and an emitter 4 are subsequently diffused. First, each junction hole of the emitter and the base is etched. An emitter junction hole 5 is covered with resist, after stopping etching at the completion of the hole 5, and a base junction hole 6 is made. When the hole 5 is opened, a field 7 forming a field plate is etched at the same time, and the SiO2 film is reduced in its thickness. It is reduced to the same thickness for the emitter and the base, then, electrodes 8, 9, and a field plate 10 are attached thereupon. This constitution produces the high dielectric strength by the field plate of a planer transistor very effectively without increasing the number of processes. |
