FORMING METHOD OF INSULATION REGION IN SEMICONDUCTOR SUBSTRATE

摘要

PURPOSE:To form an insulation region at a deep position inside a semiconductor substrate by making porous a P type region formed through irradiation of a light element charged particle and the resorting to oxidation means. CONSTITUTION:A P type semiconductor region 4 having a thickness W at a position D from the main surface 2 of a semiconductor substrate 1 in the said semiconductor substrate by irradiating a light element charged electron beam 3 consisting of proton, deutron or helium ion on the N type semiconductor base 1 from its two sides. Next, anodic formation on the semiconductor region 4 is performed, so that the said region is porous. After this process, the semiconductor substrate 1 is arranged in a heated oxygen atmosphere to make the porous region an insulated isolation region 6. Then a semiconductor circuit is formed on the insulated isolation region 7. Thus a semiconductor device where an insulated region is formed way deep inside the substrate, can be obtained.