Ultra-wide temperature area high-thermal-stability microwave power SiGe heterojunction bipolar transistor

Abstract

The invention discloses a heterojunction bipolar transistor, and particularly relates to an ultra-wide temperature area high-thermal-stability microwave power SiGe heterojunction bipolar transistor. According to the ultra-wide temperature area high-thermal-stability microwave power SiGe heterojunction bipolar transistor, a stepped distribution structure that the number of base region Ge components gradually increases from an emitter junction side to a collector junction side is adopted, current gain of a device slows down along with the trend of temperature changes, and drifting of a quiescent operating point of the device can be prevented in a wide temperature area; meanwhile, the ultra-wide temperature area high-thermal-stability microwave power SiGe heterojunction bipolar transistor can improve the characteristic frequency of the device and sensitivity of changes, along with the temperature, of the device. In addition, due to the fact that the non-equal finger separation distance symmetrical structure that indexes of the finger separation distances of emitter electrode fingers increase from the two sides of the device to the center of the device is further adopted by the ultra-wide temperature area high-thermal-stability microwave power SiGe heterojunction bipolar transistor, the phenomenon that heat of emitter electrode fingers on the outer side flows into the center can be effectively prevented from happening, the purpose of reducing thermal coupling effect among emitter electrode fingers and the purpose of improving uniformity of distribution of the temperature of an active area of the device are achieved, and the purpose of improving the thermal stability of the ultra-wide temperature area high-thermal-stability microwave power SiGe heterojunction bipolar transistor is achieved.

Description

technical field [0001] The invention relates to a silicon germanium (SiGe) heterojunction bipolar transistor, in particular to a SiGe heterojunction bipolar transistor with ultra-wide temperature range and high thermal stability used in radio frequency and microwave fields such as satellite systems, optical fiber communication systems and winmax. Background technique [0002] Compared with Si homojunction bipolar transistors (bipolar junction transistors, BJT), SiGe heterojunction bipolar transistors (heterojunction bipolar transistors, HBT) have high current handling capability, large current gain and high Early voltage at the same time, It also has excellent high-frequency characteristics, and has been widely used in mobile phone systems, Bluetooth, satellite positioning systems, automotive radar and other fields. Especially, with the rapid development of optical fiber communication, satellite communication and winmax technology, power SiGe HBT will play an increasingly im...

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Problems solved by technology

However, for a conventional SiGe HBT with a constant base Ge component content, its I pb Has a large positive temperature coefficient, when the operating temperature of the device increases, I pb will increase significantly such that the current gain has a negative temperature coefficient

Further considering the extremely uneven temperature distribution on each emitter finger caused by self-heating and thermal coupling effects, there will be a phenomenon of "collapse" of the current gain, degrading the working characteristics of the device (such as power gain, characteristic frequency, etc.), causing the device And circuit characteristics drift, making SiGe HBT in a thermally unstable state, which seriously limits the high-power thermal stability of the device

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