| 摘要 |
PURPOSE:To prevent thermal runawoy and to keep the saturation voltage of the collector and emitter low by making a resistance layer which has negative temperature dependence on a surface-insulated film of an Si substrate in such a manner as to be connected to a base and emitter layer and covered therwith. CONSTITUTION:The resistance layer 4 of a p type Si is provided on an SiO2 film 10 connected to electrodes 1 and 2 of a base 7 and an emitter 3. Doping quantity for the poly Si is selected to control the resistance value and the temperature coefficient negative. When Al is used for the electrodes, the use of p type impurities facilitates the ohmic contact. To detect the junction temperature accurately, the resistance layer 4 is made across the emitter 3 and the base 7. In addition, when provided entirely covering SiO2 10, the resistance layer 4 can ease the accumulation of electric charge on the film 10 while there is no increase in the leak from the collector and base junction. This prevents thermal runawoy while lowering the saturation voltage of the collector and emitter. Thus, a device can be obtained with limited characteristic variation due to the accumulation of electrical charge. |
