Gerry McCarthy, the recently appointed managing director of the US technology giant’s Scottish operation, which is the last remaining hi-tech manufacturer in Inverclyde, also told The Herald that the company’s future in Scotland is “secure”.

In an exclusive interview with The Herald, Mr McCarthy, who was promoted to head the Renfrewshire site in July, described the latest investment plan as “another ringing endorsement” for the site.

Even though most technology companies held up better than their counterparts in other sectors during the recession – because they produce the tools that increase efficiencies, reduce costs and make it easier to operate globally – NatSemi’s latest investment figure, double the previous year’s investment, is both sizeable and notable.

The California-based company, which produces analogue semiconductors and has been in Greenock since 1970, proved itself to be one of the most resilient technology companies during the downturn. It has also recently brought its headcount – a mix of temporary contract workers and permanent staff – back up to the 450 mark.

Analogue chips tweak real-world information such as sound and light, as they move through digital products such as mobile phones, MP3 players, iPods and high-definition televisions.

NatSemi’s silicon analogue chips are found in devices that use batteries and power-management, wireless devices and also wireless network infrastructures, which are increasingly under pressure from the growing demands to carry the high-speed data necessary for richer internet and video features on mobile phones.

Mr McCarthy said: “We have had a very good front half of the year, largely driven by growth in mobile infrastructure development in places like China and India.

“We’re also increasing the size of the semiconductor wafers we manufacture here from 150mm to 200mm, which offers 20% cost and productivity improvements.

“Much of the £20 million investment will go into the new machinery and technology to make that transfer possible.”

At the same time, NatSemi’s larger wafers are being designed more innovatively with structures, such as MEMS, on top for added functionality.

MEMS, or micro-electrical-mechanical sensors, are nano devices that often use the motions of tiny silicon fingers to detect sound or movement. In vehicle airbag systems, for example, MEMS chips detect the shock of a collision and deploy the bag, and MEMS have been used as microphones in low-cost electronic devices.

Mr McCarthy said: “This is a very big endorsement in NatSemi’s faith in the Greenock operation and its future.

“We have a lot more responsibility now because NatSemi has only two plants and we are one of them.”

As part of the company’s strategy to cope with the impact of the recession, NatSemi last year closed its silicon-wafer plants in Arlington, Texas and China. However, it was a move that saw additional operations move to its remaining plants in Greenock and South Portland, Maine.

At the same time, Mr McCarthy also said the company has been quietly increasing its staff on the back of rising demand and over the past year - taking it back to the pre-downturn level of 2007.

He said the company had added around 150 to its headcount over the last 12 months, bringing it up to around 450, after enforcing a number cuts early in 2009, during the worst of the downturn.

Globally, NatSemi last year cut around 1700 jobs globally, about a quarter of its workforce, as recession gnawed at its sales.

Among those layoffs were 39 at the Greenock plant, which took the headcount to around 300.

Mr McCarthy added: “Over the past year, we raised our permanent plant staff from 108 to around 200, bringing them over from the temporary workforce to permanent staff, and we’ve also added a number of engineering and technical staff.”

Asked if he expected more temporary staff to be given permanent positions, he said: “Our business has definitely stabilised, and, yes, we gradually hope to take on more people on a permanent basis.

“But the global recovery is tentative, and if the economy were to go down again, we need to be best-placed to cope with that, at a staffing level.”

NatSemi’s development and manufacturing centre in Greenock was established in 1970.

The site, one of the company’s two silicon-wafer plants and the only one outside the US, currently employs around 450 staff.

The plant designs and produces analogue semiconductors, used in power-management, wireless devices and wireless network infrastructure.