Mitsubishi Denki Kabushiki Kaisha

Toshiaki Hikichi

Ikunori Takata

A Darlington transistor having improved comprehensive electric characteristic and a bipolar transistor having improved high voltage characteristic are obtained. A collector resistivity .rho.N.sup.- (F) of a collector high resistivity layer (11) in a front stage side transistor chip (TF) is set to 80 5/8cm and its collector film thickness tN.sup.- (F) is set to 120 .mu.m, and a collector resistivity .rho.N.sup.- (R) of a collector high resistivity layer (13) in a rear stage side transistor chip (TR) is set to 45 .OMEGA.cm and its collector film thickness tN.sup.- (R) is set to 160 .mu.m. Since .rho.N.sup.- (F)&gt;.rho.N.sup.- (R) and tN.sup.- (F)&lt;tN.sup.- (R) are satisfied, a Darlington transistor having a good comprehensive electric characteristic can be obtained, and also, since .rho.N.sup.- (R)/tN.sup.- (R)&lt;0.6 is satisfied, a bipolar transistor having a good high voltage characteristic can be obtained (FIG. 8).

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Fukuoka, Japan

Toshiaki Hikichi