Process for Yield Improvement in Bipolar Devices
Original Publication Date: 1980-Jun-01
Included in the Prior Art Database: 2005-Feb-13
A process is described which will cause retention of dissolved oxygen in solution during the early stages of hot processing, which is when excessive precipitation prior to epitaxial growth has been shown to cause a decrease in device yields, and will then cause the nucleation and precipitation of oxygen to form SiO(2) precipitates later in the process, and thus provide multiple gettering sites within the wafers. Some of the key features of this process which use existing process technologies are as follows: 1) Use swirl-free silicon wafer having oxygen concentrations in the range of 20 to 30 ppma. 2) Eliminate the crystal and/or wafer annealing normally used in wafer production. 3) Increase the "first oxidation" temperature to >/- 1,000 degrees C.