Manufacture of derivative isolating substrate

Abstract

Abstract PURPOSE:To prevent the lowering of operation efficiency resulting from the warpage of the substrate by adding an element with an atomic radius different from silicon. CONSTITUTION:Since a single crystal base body 1 and polycrystal silicon 4 have different structure through they are made of the same element, their thermal expansion coefficients differ, and they have large internal stress. When comparing both thermal expansion coefficients, the polycrystal silicon 4 is larger, and the single crystal side is warped so as to be projected. However, the states of warpages change to concave form (at the single crystal side) from convex form with the repetition of heat treatment in the oxidizing atmosphere. There is a warpage through which operation efficiency hardly lowers substantially in the warpages of the substrate, and the warpage through which the single crystal side is projected belongs to the warpage. A large quantity of the elements with the atomic radii smaller than silicon are sufficiently added in a deposition process in the polycrystal silicon 4, and layers 5 are ones to which the element is added. The single crystal side is protruded in the substrate by compression type internal stress induced because a large quantity of the elements with the small atomic radii are added.

Inventors

• 👤 Teruo Kusaka
• 👤 日下　輝雄

Bibliographic Details