Physics, technology, and modeling of polysilicon emitter contacts for VLSI bipolar transistors
Polysilicon contacts to the base and emitter of bipolar transistors have played a key role in improving the switching speed and packing density of bipolar integrated circuits. One improvement that results from contacting the emitter with polysilicon instead of metal is that the base current of the device is significantly reduced. No model currently exists to adequately explain the electronic properties of these contacts. The difficulties that have arisen in modeling minority-carrier transport in polysilicon-contacted emitters can be largely attributed to the complex and poorly understood nature of the polysilicon/single-crystal silicon interface. The objective of this work was to provide a better understanding of polysilicon emitter contacts. To that end, a series of experiments were performed that examine most of the relevant material and processing parameters and correlate the structure of the polysilicon/monosilicon interface to the electrical characteristics of the transistor. In addition, a novel approach was taken in the modeling of transport effects in these emitters to quantify the minority-carrier blocking properties of the polysilicon contacts. Device with native or chemical oxides between the polysilicon and single-crystal silicon regions were considered in this work. Experimental results show that extremely low values of base current can be obtained without resorting to the use of chemical oxides.
- Research Organization:
- Stanford Univ., CA (USA)
- OSTI ID:
- 6710873
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ELECTRIC CONTACTS
INTEGRATED CIRCUITS
SWITCHING CIRCUITS
TRANSISTORS
CARRIER MOBILITY
MONOCRYSTALS
POLYCRYSTALS
SILICON
CRYSTALS
ELECTRICAL EQUIPMENT
ELECTRONIC CIRCUITS
ELEMENTS
EQUIPMENT
MICROELECTRONIC CIRCUITS
MOBILITY
SEMICONDUCTOR DEVICES
SEMIMETALS
420800* - Engineering- Electronic Circuits & Devices- (-1989)
990220 - Computers
Computerized Models
& Computer Programs- (1987-1989)