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LDD Sidewall Spacers Without Reactive Ion Etch

IP.com Disclosure Number: IPCOM000044593D
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Mohler, RL: AUTHOR [+2]

Abstract

Lightly doped drain (LDD) technology relies on sidewall spacers to produce improved source-drain (S/D) diffusion profiles. A simplified process is provided to replace reactive ion etching (RIE) of LDD oxide sidewall spacers. The process for arriving at the complete LDD structure without RIE is as follows: 1. Define the gates (as in a typical field-effect transistor (FET) or complementary metal-oxide-semiconductor (CMOS) process just after the polysilicon gate 11 etch) (Fig. 1). 2. Lightly dope the S/D regions 12 with appropriate energy, dose, species (optional step) (Fig. 2). 3. Deposit a conformal layer of low pressure chemical vapor deposition (LPCVD) SiO2 13 of an appropriate thickness (1000 - 3000 A) (Fig. 3). 4. CVD anneal at this time (optional).

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LDD Sidewall Spacers Without Reactive Ion Etch

Lightly doped drain (LDD) technology relies on sidewall spacers to produce improved source-drain (S/D) diffusion profiles. A simplified process is provided to replace reactive ion etching (RIE) of LDD oxide sidewall spacers. The process for arriving at the complete LDD structure without RIE is as follows: 1. Define the gates (as in a typical field-effect transistor (FET) or complementary metal-oxide- semiconductor (CMOS) process just after the polysilicon gate 11 etch) (Fig. 1). 2. Lightly dope the S/D regions 12 with appropriate energy, dose, species (optional step) (Fig. 2). 3. Deposit a conformal layer of low pressure chemical vapor deposition (LPCVD) SiO2 13 of an appropriate thickness (1000 - 3000 A) (Fig. 3).
4. CVD anneal at this time (optional). The SiO2 13 is rendered more "etchable" by this anneal, and the etch rate is stabilized. 5. Perform an SiO2 "damage/doping" ion implant 14 with either an inert gas, such as argon, or a dopant material, such as arsenic. This implant 14 is designed to penetrate or damage the planar portion of the SiO2 13, allowing the SiO2 13 to be etched at a much faster rate than the undamaged/undoped sidewall SiO2 portion 15. The SiO2 covering the sidewall 15 would not be implanted, being of a much thicker vertical thickness (Fig. 5). 6. Perform etching in a buffered hydrofluoric acid (BHF). The time is "to be determined" and depends on the total thickness of the deposited SiO2 13. A...