High performance SiGe:C HBT with phosphorous atomic layer doping

US8115196B2 · kind B2 · utility

Assignee

• NATIONAL SEMICONDUCTOR CORPORATION · US

Inventors

• Janial Ramdani · Scarborough, US
• Craig Printy · Hollis, US
• Thanas Budri · Portland, US

Key dates

• Filing date: Feb 21, 2011
• Grant date: Feb 14, 2012
• Expiry date: Feb 21, 2031

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/02617
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A base structure for high performance Silicon Germanium:Carbon (SiGe:C) based heterojunction bipolar transistors (HBTs) with phosphorus atomic layer doping (ALD) is disclosed. The ALD process subjects the base substrate to nitrogen gas (in ambient temperature approximately equal to 500 degrees Celsius) and provides an additional SiGe:C spacer layer. During the ALD process, the percent concentrations of Germanium (Ge) and carbon (C) are substantially matched and phosphorus is a preferred dopant. The improved SiGe:C HBT is less sensitive to process temperature and exposure times, and exhibits lower dopant segregation and sharper base profiles.