Method for making a lateral PNP or NPN with a high gain utilizing reactive ion etching of buried high conductivity regions

The method for making lateral PNP transistors comprising:

• providing a silicon semiconductor body having an N+ buried region therein;
• reactively ion etching regions of said body to form openings in the areas where dielectric isolation is desired to isolate regions of monocrystalline silicon;
• the etch rate of the said reactive ion etching is adjusted to cause a preferential etching of the said N+ region so that a portion of the said N+ region is removed and monocrystalline silicon remains above this removed portion;
• filling the said openings with a dielectric material wherein a portion of said monocrystalline region has a dielectric material under this region;
• simultaneously forming the P type emitter and collector regions with the emitter region being formed in said portion of said monocrystalline region having dielectric isolation thereunder wherein there is no vertical junction between the said P type emitter and said buried N+ region;
• and
• making electrical contacts to the emitter, base and collector regions to form said PNP lateral transistor.