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Obtaining Differing Multiple Doping Profiles from a Single Diffusion

IP.com Disclosure Number: IPCOM000081472D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Hornung, A: AUTHOR [+2]

Abstract

Specific surface concentrations and doping profiles in integrated circuit devices are conventionally obtained, by diffusion of dopants for semiconductor materials directly into the semiconductor substrate. Complex device structures require numerous diffusion steps, in order to obtain the differing surface concentrations and doping profiles required. For example, the doping concentration of different resistors frequently requires different diffusion operations. This adds to the complexity and cost of the fabrication.

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Obtaining Differing Multiple Doping Profiles from a Single Diffusion

Specific surface concentrations and doping profiles in integrated circuit devices are conventionally obtained, by diffusion of dopants for semiconductor materials directly into the semiconductor substrate. Complex device structures require numerous diffusion steps, in order to obtain the differing surface concentrations and doping profiles required. For example, the doping concentration of different resistors frequently requires different diffusion operations. This adds to the complexity and cost of the fabrication.

In this process, resistivity regions having differing surface concentrations and depths can be produced in a semiconductor substrate, utilizing a single-diffusion operation. The objective is achieved by providing relatively thin SiO(2) layers over the diffusion masking window, in order to slow up or impede the dopant in the selected regions.

In this process, a layer 10 of SiO(2) or other suitable material for a masking layer is deposited or formed on semiconductor substrate 12. Using conventional photolithographic techniques, an opening 14 is made in layer 10, as shown in Fig. 2. A relatively thin layer 15 is formed in the opening 14, as shown in Fig. 3. The thickness of layer 15 is dependent on the desired nature of the subsequent diffusion. As shown in Fig. 4, for purposes of illustration, a second diffusion window 16 is made in layer 10 and the resultant structure exposed to a dop...