| 摘要 |
PURPOSE:To implement a high withstanding voltage of an element, by tightly bonding the mirror surfaces, which are formed on the surfaces of semiconductor substrates having the same conducting type and also having the difference in concentration, and forming a compound semiconductor substrate as a unitary body. CONSTITUTION:An oxide film 12 is provided by a thermal oxidation method on the surface of an N<+> type low resistance silicon substrate. Then, silicon nitride 13 is deposited by a chemical vapor deposition method, and patterning is performed. The exposed oxide film 12 is removed by a photoetching method. After the silicon substrate 10 is etched, it is grown to a specified thickness by high temperature thermal oxidation. The silicon nitride layer 13 is removed. Meanwhile, an N<-> type high resistance silicon substrate 14 is prepared and bonded to the N<+> type low resistance silicon substrate 10, in which the thin oxide film 12 is embedded. The bonding surfaces of both silicon substrates 10 and 14 are polished to obtain mirror surfaces and washed by clean water. A dehydrating process such as spinner process is performed at a room temperature. Under the state foreign matters are substantially not present between the mirror surfaces of the silicon substrates, the mirror surfaces are closely contacted, and junction layer is formed. Thus, a unitary body is formed. Then reverse conducting type impurities are introduced from the surface of the compound semiconductor substrate, and a P-N junction is formed. at this time, the end parts of the junction are exposed on the surface of the compound semiconductor substrate. |
