SEMICONDUCTOR DEVICE

PURPOSE:To improve yield and reliability by a method wherein the specified area of substrate and surface step difference of synchronous type RS flip-flop circuit are reduced utilizing hetero-junction bipolar transistors as elements. CONSTITUTION:N type GaAs layers 22, 26, n type AlGaAs layers 23, 25 and a p type GaAs layer 24 are respectively formed on a semi-insulated GaAs substrate. Besides element separating regions 27A, 27B implanted with protion or O ion and element separating regions 27B between transistor elements T1- T2-T3and T4-T5-T6 are terminated in an n type AlGaAs layer 23 while the regions in the layer 23 are mutually connected by an n type GaAs layer 22. Moreover, 28 is a p type region, 31 is a base electrode, 32C and 32E are electrodes while as for the transistor element T1 and T4, layers 23 and 25 are respectively a collector and an emitter; as for T2, T3, T5 and T6, layers 23 and 25 are reversely an emitter and a collector assuming 32C and 32E respectively to be a collector electrode and an emitter electrode.