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Chapter 13 Future Directions. 學生:郭智昇 學號: R91943036. Technology Trends. Technology Trends. SiGe HBT can be viewed as an “ adder ” to a high-speed CMOS core technology without perturbing the characteristics of the underlying core CMOS. SiGe 有優於 GaAs 的高集積度、高電子傳導率與高製造良率的競爭優勢
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Chapter 13Future Directions 學生:郭智昇 學號:R91943036
Technology Trends • SiGe HBT can be viewed as an “adder” to a high-speed CMOS core technology without perturbing the characteristics of the underlying core CMOS
SiGe有優於GaAs的高集積度、高電子傳導率與高製造良率的競爭優勢SiGe有優於GaAs的高集積度、高電子傳導率與高製造良率的競爭優勢 • 與矽比較,SiGe在高頻環境下擁有低雜訊、低功率損耗的優點 • 可同時整合FET與Bipolar也是SiGe的發展優勢 • SiGe的用途涵蓋功率放大器、無線通訊的行動電話、Bluetooth、DECT等之RF IC、SoC或光纖骨幹網路SONET介面IC
SiGe製程技術 • HBT • HFET • Optoelectronic
SiGe HBT與Si-Bipolar相容,可透過三種不同的磊晶成長技術-Selective、Differential、Blanket發展 • SiGe HBT元件結構分成Doublepoly Selfaligned、Singlepoly Quasi-selfaligned、Mesatype
SiGe HFET元件結構分成MOSFET與QW MOSFET二種,其中QW MOSFET適用於低電壓及高傳輸率的系統環境 • Optoelectronic發展目的完全以光電IC為主,包含光電檢測器、光纖節點、光纖高速IC、光導波管、光波通訊微機電開關等
Technology Trends • Multiple breakdown voltage versions of the core SiGe HBT will be available on the same die for greater circuit design flexibility • Carbon doping of SiGe HBT will become the mainstream makes thermal budget and profile control that much easier
Technology Trends • Higher C content(2-3%) to produce SiGeC alloys that are lattice-matched directly to Si • While SiGeC alloys with up to 3% C ,it seems unlikely that lattice-matching within the SiGe/Si system
Technology Trends • First generation SiGe HBT • fT,Peak=50 GHz • Second generation performance level • 100—120 GHz peak fT • Third generation performance level • >200 GHz peak fT
Technology Trends • SiGe technology will increaseingly move to full copper metalization to support the requisite high device current densities as well as improve the Qs of the passives
Four approaches that might be used to improve the high-freq losses in SiGe (1)Move to high-resistivity substrates (2)Use thicker top-side dielectrics,combined with lower resistivity metal(Cu) (3)use postfabrication spun-on polymers followed by Cu or Au for passives and transmission lines (4)move to SiGe on SOI
Noise coupling • Using conservative layout approaches and intelligent placement of critical noise sensitive functions • e.g. do not put your LNA next to a large CMOS digital switching block • Deep-trench feature provides excellent noise isolation
The peak fT in each SiGe technology generation occurs at roughly the same bias current • meaning that the collector current density is rising rapidly the level of demonstrated performance • Power saving potential for SiGe clearly holds great leverage for portable(battery-limited) system
What is the practical performance limit of a commercially visible SiGe HBT technology? • Attainable fmax is difficult • Breakdown voltage must decrease as the transistor performance improve