Patent ID: 7285455
Filing Date: 2007-10-23
Classification: H01L

Abstract:
1. A method of producing a semiconductor device, comprising the steps of: forming a first oxide layer, a first single crystal silicon layer, a second oxide layer, and a second single crystal silicon layer on a support substrate in this order to prepare a double SOI substrate; etching the second single crystal silicon layer in a bipolar transistor forming area on the double SOI substrate from a front surface of the double SOI substrate down to a depth where the first oxide layer is exposed to form a deep trench, depositing a silicon nitride layer and a silicon oxide layer on the double SOI substrate to fill the deep trench, etching the bipolar transistor forming area down to a depth where the second oxide layer is exposed to form an opening, removing the second oxide layer in the bipolar transistor forming area with wet etching to form a cavity, depositing a polycrystalline silicon layer in the opening and the cavity, and forming a bipolar transistor on the second single crystal silicon layer in the bipolar transistor forming area.