In　this　paper,　the　structure　and　fabrication　of　a　type　of　SiGe　HBT　with　quantum　well　base　region　are　introduced　and　analyzed.　Basing　on　this,　the　high　frequency　equivalent　circuit　model　of　SiGe　HBT　with　modulation　doped　quantum　well　base　region　has　been　presented.　Moreover,　the　elements　of　the　model　are　calculated　according　to　the　material　structure　and　fabricating　size.　Then　the　high　frequency　characteristics　are　simulated　and　explained　from　the　circuit　model.　The　simulation　results　are　in　good　agreement　with　that　of　the　test.　The　cut　off　frequency　fT=16GHz　and　the　maximum　oscillation　frequency　fmax=8GHz　for　the　sample.　It　is　of　both　higher　cut　off　frequency　and　the　maximum　oscillation　frequency　fmax　than　the　SiGe　HBT　without　quantum　well　base　region　with　the　same　size.　When　the　fabricating　size　of　SiGe　HBT　with　quantum　well　base　has　been　changed,　the　model　still　be　effective,　only　the　value　of　the　elements　of　the　model　should　be　evaluated　again.　©　2004　IEEE.