Methods of making implanted structures

US6309975A · kind A · utility

Assignee

• Micron Technology, Inc. · US

Inventors

• Zhiqiang Wu · Plano, US
• Li Li · Meridian, US
• Thomas A. Figura · Boise, US
• Kunal R. Parekh · Boise, US
• Pai-Hung Pan · Boise, US
• Alan R. Reinberg · Boise, US
• Kin F. Ma · Boise, US

Key dates

• Filing date: Mar 14, 1997
• Grant date: Oct 30, 2001
• Expiry date: Mar 14, 2017

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D30/0223
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

Methods are disclosed for forming shaped structures of silicon-containing material with ion implantation and an etching process which is selective to silicon-containing material implanted to a certain concentration of ions or with an etching process which is selective to relatively unimplanted silicon-containing material. In general, the methods initially involve providing a layer of silicon-containing material such as polysilicon or epitaxial silicon on a semiconductor substrate. The layer of silicon-containing material is then masked, and ions are implanted into exposed portions of the layer of silicon-containing material. The mask is removed, and the aforementioned selective etching process is conducted to result in one of an implanted and a relatively unimplanted portion of the layer of silicon-containing material being etched away and the other left standing to form a shaped structure of silicon-containing material. One preferred selective etching process uses an etchant solution comprising a selected weight percentage of tetramethyl ammonium hydroxide in deionized water. The etchant solution etches relatively unimplanted silicon-containing material implanted up to 60 times fa…