Application of low-impurity concentration (high-resistivity) Si epitaxial technique to high-voltage power transistors

The results of an application of an epitaxial technique of low-concentration (<1 × 10
¹⁴
atoms/cm
³
) impurity doping control to high-voltage power transistors (BV
CB0
= 1200 V, I
c
= 2.5 A) are described. An n-epitaxial layer of about 1 × 10
¹⁵
atoms/cm
³
concentration and about 25-µm thickness and ν-epitaxial layer of 5-8 × 10
¹³
atoms/cm
³
concentration and 155-165- µm thickness are successively grown on the n
⁺
-substrates to form the collector region. The p-base and n
⁺
-emitter regions are formed by diffusion. It is shown that the transistors fabricated have a collector-base breakdown voltage (BV
CB0
) of 1400-2300 V and other reasonable electrical characteristics.